i

w fmd i ^Wiia fmltamp

ridhk uacuteoHdj

12 fYaKsh

iiumlma fmd

04 tallh - modfrac34fha jdhquh wjiadj

05 tallh - Ylas uacuteoHdj

uacuteoHd fomdfrac34fiumlka=j uacuteoHd yd dlaIK mSGh

cdsl wOHdmk wdhkh uyru

wwwnielk

ii

ridhk uacuteoHdj

iiumlma fmd

12 fYaKsh

copy cdsl wOHdmk wdhkh

mltuq uqoslashKh ndash 2019

uacuteoHd fomdfrac34fiumlka=j

uacuteoHd yd dlaIK mSGh

cdsl wOHdmk wdhkh

YS xld

mldYkh ( uqoslashKdh

cdsl wOHdmk wdhkh

uyru

YS xld

iii

wOHCI ckrdafa mKsuacutevh

wOHdmkfha =KdaulNdjh jfrac34Okh lsIacuteu i|yd cdsl wOHdmk wdhkh jszligka jr

wjiadkql+ mshjr kq nhs wodlt uacuteIhhka i|yd wsffrac34l iiumlma fmda ilia lsIacuteu tjka

tla mshjrls

cdsl wOHdmk wdhkfha uacuteIhudd ixjfrac34Ok lKavdhua cdsl uacuteYaj uacuteoHdj uacuteoaj=ka

iy mdiea moaOsfha mltmqreyuml =rejreka uska wsffrac34l iiumlma fmda ilia lr we 2017 sect

lshdaul lrk o wfmdi ^Wiia fmltamp kj uacuteIh ksfrac34foaYhg wkqj fuu wsffrac34l iiumlma

fmda shd wes ksid isiqkag wodlt uacuteIh lreKq msltsn|j wjfndaOh mqiquesta llt yels wr

jvda ModhS bfkqiuml bekaugraveiuml lshdldrliuml ieiqiuml lsrSug =rejrekag fiumljd mrsYSkh l

yel

cdsl wOHdmk wdhkfha ldfrac34h uKavfha idudethlhskag iy ndysr uacuteIh lafIafha uacuteoaja

uacutefYaIhkag Tn fj fuu fdr=re nd sectu i|yd Tjqkafa YdiaSh odhlajh nd sectu

fjkqfjka udfa wjxl lDdj mlt lsIacuteug leueafntilde

wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr

wOHlaI ckrda

cdsl wOHdmk wdhkh

uyru

iv

wOHCIjrhdfa mKsuacutevh

2017 jfrac34Ifha isg YS xldfotilde idudkH wOHdmk moaOsfha wfmdi ^Wiia fmltamp i|yd

dfrac34lSlrKhg la llt kj uacuteIhuddjla lshdaul fotilde bka woyia jkafka fufla mejs

uacuteIhuddj hdjaldSk lsIacuteuls fiuml ldfrac34hfha sect wfmdi ^Wiia fmltamp ridhk uacuteoHdj

fNsl uacuteoHdj yd Ocircj uacuteoHdj hk uacuteIhj uacuteIh ikaOdrfhaa uacuteIh wdlDsfhaa uacuteIhudd

oslashjHja hiuml hiuml ixfYdaOk isyuml l wr Bg iudoacutej bfkqiuml-bekaugravefiuml lufotildeofhaa

wehSiuml yd lafiarelrKfhaa hiuml hiuml fjkiaugraveiuml wfmalaId lrk Egrave uacuteIhudfotilde wvx=

uacuteIh lreKqj mudKh uacuteYd jYfhka wvq lrk o wr bfkqiuml-bekaugravefiuml wkqqlufha

hiuml hiuml fjkiaugraveiuml o isyuml lrkq eicirc h mejs uacuteIhudd oslashjHhla jQ =re udfrac34fdamfoaY ixyh

fjkqjg =re wafmdla ydividekajd fok Egrave

Wiia fmlt uacuteoHd uacuteIh i|yd bxSis NdIdfjka iiumlmdEgrave wkafrac34cdsl jYfhka msltsa ka

mszligYSkh miqsh uacuteIhudd lshdaul lsIacutefiuml sect wHjYH uacuteh tfya uacuteuacuteO fmltfmda Nduacute

lsIacutefiuml sect mriamruacutefrdaO uacuteIh lreKq i|yka ugraveua foaYSh uacuteIhuddfotilde iSud wNsNjd sh uacuteIh

lreKq tajdfha we=iquesta ugraveua ksid =reNj=kag yd isiqkag ta ka mszligyrKh myiq jQfha

ke fiuml kah Tn wg ma jkafka ta wjYHdj imqrdSug a Waidyhl msMhla

fi h

tneuacuteka fiuml kah u`ska foaYSh uacuteIhuddfotilde iSudjg hgaj ish ujqNdIdfjka wodlt uacuteIh

ikaOdrh mszligyrKh lsIacuteug isiqkag wjiadj iid we tfuka u uacuteuacuteO ka wsffrac34l mkas

jeks uQdYhjska wjYH fdr=re nd ekSu fjkqjg uacuteIhuddj u`ska wfmalaIs

fdr=re =reNj=kag yd isiqkag ksjerEgravej nd ekSug fiuml kah Wmldszlig jkq we

uacuteIh iiumlkaO uacutefYaI =reNj=ka yd uacuteYajuacuteoHd wdpdfrac34hjreka uacuteiska iiumlmdEgrave fiuml kah

cdsl wOHdmk wdhkfha uacuteIhud lntildegqfjka o wOHhk uKavfhka o mdl iNdfjka o

wkquesh nd Tn wg ma jk neuacuteka bylt mntildesfhka hq= nj ksfrac34foaY llt yels h

wdpdfrac34h ta atilde wfidal o isajd

wOHlaI

uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

v

wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr

wOHlaI ckrda cdsl wOHdmk wdhkh

weumllaIKh wdpdfrac34h ta auml ta o isajd

wOHlaI uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

uacuteIh kdhlajh tiuml tia uacuteluisxy

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh

wNHkar ixialrK uKavh ta fla jvqfa uhd

fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j

lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh

uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh (04 jk tallh)

ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh

fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh

uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j

wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07

iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv

vi

NdId ixialrKh

cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK

fala yjqia fldltU 10

uqa msgqj

wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh

uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd

(

vii

mgqk

wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii

wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv

uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v

04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27

11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02

12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05

121 jdhq kshu

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)

123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)

124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)

125 ujqsl mszligudj (Vm)

126 ixhqla jdhq ioacutelrKh

13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16

131 ujq Ndh wkqidrfhka wdxYsl mSvkh

14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18

141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk

142 pdl wKqljdofha ioacutelrKh

143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh

144 ueialafja-fndaaUumliaudka jHdmash

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23

151 jeka vrsquojdaia ioacutelrKh

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54

21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34

213 moaOshl =K

214 moaOshl wjiadj

215 tkaeamsh (H)

216 dmh

22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34

iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh

23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49

tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

1

wkafrac34 h

1 1 modfrac34fha wjiad =fkys wxY= ieleiau

iy tajdfha ofrac34YSh CIK

1 2 jdhquh wjiadj

1 2 1 jdhq kshu

bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq

ioacutelrKh

bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ

Kkh lsIacuteiuml

1 2 2 fndhsa kshuh

(mSvk-mszligud iiumlnkaOh)

1 2 3 pdaia kshuh

(WIaKajndashmszligud iiumlnkaOh)

1 2 4 wej dacircfrda kshuh

(mudK-mszligud iiumlnkaOh)

1 2 5 ujqsl mszligudj (Vm)

1 2 6 ixhqla jdhq ioacutelrKh

1 3 fvdaagkaf a wdxYsl mSvk kshuh

1 3 1 ujq Nd h wkqidrfhka

wdxYsl mSvkh

1 4 jdhq msltsn`o pdl wKql jdoh

1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla

i|yd Wmlamk

1 4 2 pdl wKql jdofha ioacutelrKh

1 4 3 jfrac34 uOHkH uQ fotilde h iy

uOHkH fotilde h

1 4 4 ueialafja--fndaaUumliaudka jHdmash

1 5 daauacutel jdhqjg eltfmk mszligEgrave

mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

1 5 1 jeka vrsquojdaia ioacutelrKh

1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

1 modfrac34fha jdhquh

wjiadj

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

ii

ridhk uacuteoHdj

iiumlma fmd

12 fYaKsh

copy cdsl wOHdmk wdhkh

mltuq uqoslashKh ndash 2019

uacuteoHd fomdfrac34fiumlka=j

uacuteoHd yd dlaIK mSGh

cdsl wOHdmk wdhkh

YS xld

mldYkh ( uqoslashKdh

cdsl wOHdmk wdhkh

uyru

YS xld

iii

wOHCI ckrdafa mKsuacutevh

wOHdmkfha =KdaulNdjh jfrac34Okh lsIacuteu i|yd cdsl wOHdmk wdhkh jszligka jr

wjiadkql+ mshjr kq nhs wodlt uacuteIhhka i|yd wsffrac34l iiumlma fmda ilia lsIacuteu tjka

tla mshjrls

cdsl wOHdmk wdhkfha uacuteIhudd ixjfrac34Ok lKavdhua cdsl uacuteYaj uacuteoHdj uacuteoaj=ka

iy mdiea moaOsfha mltmqreyuml =rejreka uska wsffrac34l iiumlma fmda ilia lr we 2017 sect

lshdaul lrk o wfmdi ^Wiia fmltamp kj uacuteIh ksfrac34foaYhg wkqj fuu wsffrac34l iiumlma

fmda shd wes ksid isiqkag wodlt uacuteIh lreKq msltsn|j wjfndaOh mqiquesta llt yels wr

jvda ModhS bfkqiuml bekaugraveiuml lshdldrliuml ieiqiuml lsrSug =rejrekag fiumljd mrsYSkh l

yel

cdsl wOHdmk wdhkfha ldfrac34h uKavfha idudethlhskag iy ndysr uacuteIh lafIafha uacuteoaja

uacutefYaIhkag Tn fj fuu fdr=re nd sectu i|yd Tjqkafa YdiaSh odhlajh nd sectu

fjkqfjka udfa wjxl lDdj mlt lsIacuteug leueafntilde

wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr

wOHlaI ckrda

cdsl wOHdmk wdhkh

uyru

iv

wOHCIjrhdfa mKsuacutevh

2017 jfrac34Ifha isg YS xldfotilde idudkH wOHdmk moaOsfha wfmdi ^Wiia fmltamp i|yd

dfrac34lSlrKhg la llt kj uacuteIhuddjla lshdaul fotilde bka woyia jkafka fufla mejs

uacuteIhuddj hdjaldSk lsIacuteuls fiuml ldfrac34hfha sect wfmdi ^Wiia fmltamp ridhk uacuteoHdj

fNsl uacuteoHdj yd Ocircj uacuteoHdj hk uacuteIhj uacuteIh ikaOdrfhaa uacuteIh wdlDsfhaa uacuteIhudd

oslashjHja hiuml hiuml ixfYdaOk isyuml l wr Bg iudoacutej bfkqiuml-bekaugravefiuml lufotildeofhaa

wehSiuml yd lafiarelrKfhaa hiuml hiuml fjkiaugraveiuml wfmalaId lrk Egrave uacuteIhudfotilde wvx=

uacuteIh lreKqj mudKh uacuteYd jYfhka wvq lrk o wr bfkqiuml-bekaugravefiuml wkqqlufha

hiuml hiuml fjkiaugraveiuml o isyuml lrkq eicirc h mejs uacuteIhudd oslashjHhla jQ =re udfrac34fdamfoaY ixyh

fjkqjg =re wafmdla ydividekajd fok Egrave

Wiia fmlt uacuteoHd uacuteIh i|yd bxSis NdIdfjka iiumlmdEgrave wkafrac34cdsl jYfhka msltsa ka

mszligYSkh miqsh uacuteIhudd lshdaul lsIacutefiuml sect wHjYH uacuteh tfya uacuteuacuteO fmltfmda Nduacute

lsIacutefiuml sect mriamruacutefrdaO uacuteIh lreKq i|yka ugraveua foaYSh uacuteIhuddfotilde iSud wNsNjd sh uacuteIh

lreKq tajdfha we=iquesta ugraveua ksid =reNj=kag yd isiqkag ta ka mszligyrKh myiq jQfha

ke fiuml kah Tn wg ma jkafka ta wjYHdj imqrdSug a Waidyhl msMhla

fi h

tneuacuteka fiuml kah u`ska foaYSh uacuteIhuddfotilde iSudjg hgaj ish ujqNdIdfjka wodlt uacuteIh

ikaOdrh mszligyrKh lsIacuteug isiqkag wjiadj iid we tfuka u uacuteuacuteO ka wsffrac34l mkas

jeks uQdYhjska wjYH fdr=re nd ekSu fjkqjg uacuteIhuddj u`ska wfmalaIs

fdr=re =reNj=kag yd isiqkag ksjerEgravej nd ekSug fiuml kah Wmldszlig jkq we

uacuteIh iiumlkaO uacutefYaI =reNj=ka yd uacuteYajuacuteoHd wdpdfrac34hjreka uacuteiska iiumlmdEgrave fiuml kah

cdsl wOHdmk wdhkfha uacuteIhud lntildegqfjka o wOHhk uKavfhka o mdl iNdfjka o

wkquesh nd Tn wg ma jk neuacuteka bylt mntildesfhka hq= nj ksfrac34foaY llt yels h

wdpdfrac34h ta atilde wfidal o isajd

wOHlaI

uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

v

wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr

wOHlaI ckrda cdsl wOHdmk wdhkh

weumllaIKh wdpdfrac34h ta auml ta o isajd

wOHlaI uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

uacuteIh kdhlajh tiuml tia uacuteluisxy

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh

wNHkar ixialrK uKavh ta fla jvqfa uhd

fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j

lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh

uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh (04 jk tallh)

ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh

fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh

uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j

wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07

iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv

vi

NdId ixialrKh

cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK

fala yjqia fldltU 10

uqa msgqj

wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh

uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd

(

vii

mgqk

wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii

wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv

uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v

04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27

11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02

12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05

121 jdhq kshu

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)

123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)

124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)

125 ujqsl mszligudj (Vm)

126 ixhqla jdhq ioacutelrKh

13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16

131 ujq Ndh wkqidrfhka wdxYsl mSvkh

14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18

141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk

142 pdl wKqljdofha ioacutelrKh

143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh

144 ueialafja-fndaaUumliaudka jHdmash

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23

151 jeka vrsquojdaia ioacutelrKh

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54

21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34

213 moaOshl =K

214 moaOshl wjiadj

215 tkaeamsh (H)

216 dmh

22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34

iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh

23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49

tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

1

wkafrac34 h

1 1 modfrac34fha wjiad =fkys wxY= ieleiau

iy tajdfha ofrac34YSh CIK

1 2 jdhquh wjiadj

1 2 1 jdhq kshu

bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq

ioacutelrKh

bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ

Kkh lsIacuteiuml

1 2 2 fndhsa kshuh

(mSvk-mszligud iiumlnkaOh)

1 2 3 pdaia kshuh

(WIaKajndashmszligud iiumlnkaOh)

1 2 4 wej dacircfrda kshuh

(mudK-mszligud iiumlnkaOh)

1 2 5 ujqsl mszligudj (Vm)

1 2 6 ixhqla jdhq ioacutelrKh

1 3 fvdaagkaf a wdxYsl mSvk kshuh

1 3 1 ujq Nd h wkqidrfhka

wdxYsl mSvkh

1 4 jdhq msltsn`o pdl wKql jdoh

1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla

i|yd Wmlamk

1 4 2 pdl wKql jdofha ioacutelrKh

1 4 3 jfrac34 uOHkH uQ fotilde h iy

uOHkH fotilde h

1 4 4 ueialafja--fndaaUumliaudka jHdmash

1 5 daauacutel jdhqjg eltfmk mszligEgrave

mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

1 5 1 jeka vrsquojdaia ioacutelrKh

1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

1 modfrac34fha jdhquh

wjiadj

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

iii

wOHCI ckrdafa mKsuacutevh

wOHdmkfha =KdaulNdjh jfrac34Okh lsIacuteu i|yd cdsl wOHdmk wdhkh jszligka jr

wjiadkql+ mshjr kq nhs wodlt uacuteIhhka i|yd wsffrac34l iiumlma fmda ilia lsIacuteu tjka

tla mshjrls

cdsl wOHdmk wdhkfha uacuteIhudd ixjfrac34Ok lKavdhua cdsl uacuteYaj uacuteoHdj uacuteoaj=ka

iy mdiea moaOsfha mltmqreyuml =rejreka uska wsffrac34l iiumlma fmda ilia lr we 2017 sect

lshdaul lrk o wfmdi ^Wiia fmltamp kj uacuteIh ksfrac34foaYhg wkqj fuu wsffrac34l iiumlma

fmda shd wes ksid isiqkag wodlt uacuteIh lreKq msltsn|j wjfndaOh mqiquesta llt yels wr

jvda ModhS bfkqiuml bekaugraveiuml lshdldrliuml ieiqiuml lsrSug =rejrekag fiumljd mrsYSkh l

yel

cdsl wOHdmk wdhkfha ldfrac34h uKavfha idudethlhskag iy ndysr uacuteIh lafIafha uacuteoaja

uacutefYaIhkag Tn fj fuu fdr=re nd sectu i|yd Tjqkafa YdiaSh odhlajh nd sectu

fjkqfjka udfa wjxl lDdj mlt lsIacuteug leueafntilde

wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr

wOHlaI ckrda

cdsl wOHdmk wdhkh

uyru

iv

wOHCIjrhdfa mKsuacutevh

2017 jfrac34Ifha isg YS xldfotilde idudkH wOHdmk moaOsfha wfmdi ^Wiia fmltamp i|yd

dfrac34lSlrKhg la llt kj uacuteIhuddjla lshdaul fotilde bka woyia jkafka fufla mejs

uacuteIhuddj hdjaldSk lsIacuteuls fiuml ldfrac34hfha sect wfmdi ^Wiia fmltamp ridhk uacuteoHdj

fNsl uacuteoHdj yd Ocircj uacuteoHdj hk uacuteIhj uacuteIh ikaOdrfhaa uacuteIh wdlDsfhaa uacuteIhudd

oslashjHja hiuml hiuml ixfYdaOk isyuml l wr Bg iudoacutej bfkqiuml-bekaugravefiuml lufotildeofhaa

wehSiuml yd lafiarelrKfhaa hiuml hiuml fjkiaugraveiuml wfmalaId lrk Egrave uacuteIhudfotilde wvx=

uacuteIh lreKqj mudKh uacuteYd jYfhka wvq lrk o wr bfkqiuml-bekaugravefiuml wkqqlufha

hiuml hiuml fjkiaugraveiuml o isyuml lrkq eicirc h mejs uacuteIhudd oslashjHhla jQ =re udfrac34fdamfoaY ixyh

fjkqjg =re wafmdla ydividekajd fok Egrave

Wiia fmlt uacuteoHd uacuteIh i|yd bxSis NdIdfjka iiumlmdEgrave wkafrac34cdsl jYfhka msltsa ka

mszligYSkh miqsh uacuteIhudd lshdaul lsIacutefiuml sect wHjYH uacuteh tfya uacuteuacuteO fmltfmda Nduacute

lsIacutefiuml sect mriamruacutefrdaO uacuteIh lreKq i|yka ugraveua foaYSh uacuteIhuddfotilde iSud wNsNjd sh uacuteIh

lreKq tajdfha we=iquesta ugraveua ksid =reNj=kag yd isiqkag ta ka mszligyrKh myiq jQfha

ke fiuml kah Tn wg ma jkafka ta wjYHdj imqrdSug a Waidyhl msMhla

fi h

tneuacuteka fiuml kah u`ska foaYSh uacuteIhuddfotilde iSudjg hgaj ish ujqNdIdfjka wodlt uacuteIh

ikaOdrh mszligyrKh lsIacuteug isiqkag wjiadj iid we tfuka u uacuteuacuteO ka wsffrac34l mkas

jeks uQdYhjska wjYH fdr=re nd ekSu fjkqjg uacuteIhuddj u`ska wfmalaIs

fdr=re =reNj=kag yd isiqkag ksjerEgravej nd ekSug fiuml kah Wmldszlig jkq we

uacuteIh iiumlkaO uacutefYaI =reNj=ka yd uacuteYajuacuteoHd wdpdfrac34hjreka uacuteiska iiumlmdEgrave fiuml kah

cdsl wOHdmk wdhkfha uacuteIhud lntildegqfjka o wOHhk uKavfhka o mdl iNdfjka o

wkquesh nd Tn wg ma jk neuacuteka bylt mntildesfhka hq= nj ksfrac34foaY llt yels h

wdpdfrac34h ta atilde wfidal o isajd

wOHlaI

uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

v

wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr

wOHlaI ckrda cdsl wOHdmk wdhkh

weumllaIKh wdpdfrac34h ta auml ta o isajd

wOHlaI uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

uacuteIh kdhlajh tiuml tia uacuteluisxy

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh

wNHkar ixialrK uKavh ta fla jvqfa uhd

fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j

lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh

uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh (04 jk tallh)

ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh

fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh

uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j

wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07

iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv

vi

NdId ixialrKh

cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK

fala yjqia fldltU 10

uqa msgqj

wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh

uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd

(

vii

mgqk

wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii

wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv

uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v

04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27

11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02

12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05

121 jdhq kshu

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)

123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)

124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)

125 ujqsl mszligudj (Vm)

126 ixhqla jdhq ioacutelrKh

13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16

131 ujq Ndh wkqidrfhka wdxYsl mSvkh

14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18

141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk

142 pdl wKqljdofha ioacutelrKh

143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh

144 ueialafja-fndaaUumliaudka jHdmash

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23

151 jeka vrsquojdaia ioacutelrKh

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54

21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34

213 moaOshl =K

214 moaOshl wjiadj

215 tkaeamsh (H)

216 dmh

22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34

iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh

23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49

tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

1

wkafrac34 h

1 1 modfrac34fha wjiad =fkys wxY= ieleiau

iy tajdfha ofrac34YSh CIK

1 2 jdhquh wjiadj

1 2 1 jdhq kshu

bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq

ioacutelrKh

bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ

Kkh lsIacuteiuml

1 2 2 fndhsa kshuh

(mSvk-mszligud iiumlnkaOh)

1 2 3 pdaia kshuh

(WIaKajndashmszligud iiumlnkaOh)

1 2 4 wej dacircfrda kshuh

(mudK-mszligud iiumlnkaOh)

1 2 5 ujqsl mszligudj (Vm)

1 2 6 ixhqla jdhq ioacutelrKh

1 3 fvdaagkaf a wdxYsl mSvk kshuh

1 3 1 ujq Nd h wkqidrfhka

wdxYsl mSvkh

1 4 jdhq msltsn`o pdl wKql jdoh

1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla

i|yd Wmlamk

1 4 2 pdl wKql jdofha ioacutelrKh

1 4 3 jfrac34 uOHkH uQ fotilde h iy

uOHkH fotilde h

1 4 4 ueialafja--fndaaUumliaudka jHdmash

1 5 daauacutel jdhqjg eltfmk mszligEgrave

mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

1 5 1 jeka vrsquojdaia ioacutelrKh

1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

1 modfrac34fha jdhquh

wjiadj

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

iv

wOHCIjrhdfa mKsuacutevh

2017 jfrac34Ifha isg YS xldfotilde idudkH wOHdmk moaOsfha wfmdi ^Wiia fmltamp i|yd

dfrac34lSlrKhg la llt kj uacuteIhuddjla lshdaul fotilde bka woyia jkafka fufla mejs

uacuteIhuddj hdjaldSk lsIacuteuls fiuml ldfrac34hfha sect wfmdi ^Wiia fmltamp ridhk uacuteoHdj

fNsl uacuteoHdj yd Ocircj uacuteoHdj hk uacuteIhj uacuteIh ikaOdrfhaa uacuteIh wdlDsfhaa uacuteIhudd

oslashjHja hiuml hiuml ixfYdaOk isyuml l wr Bg iudoacutej bfkqiuml-bekaugravefiuml lufotildeofhaa

wehSiuml yd lafiarelrKfhaa hiuml hiuml fjkiaugraveiuml wfmalaId lrk Egrave uacuteIhudfotilde wvx=

uacuteIh lreKqj mudKh uacuteYd jYfhka wvq lrk o wr bfkqiuml-bekaugravefiuml wkqqlufha

hiuml hiuml fjkiaugraveiuml o isyuml lrkq eicirc h mejs uacuteIhudd oslashjHhla jQ =re udfrac34fdamfoaY ixyh

fjkqjg =re wafmdla ydividekajd fok Egrave

Wiia fmlt uacuteoHd uacuteIh i|yd bxSis NdIdfjka iiumlmdEgrave wkafrac34cdsl jYfhka msltsa ka

mszligYSkh miqsh uacuteIhudd lshdaul lsIacutefiuml sect wHjYH uacuteh tfya uacuteuacuteO fmltfmda Nduacute

lsIacutefiuml sect mriamruacutefrdaO uacuteIh lreKq i|yka ugraveua foaYSh uacuteIhuddfotilde iSud wNsNjd sh uacuteIh

lreKq tajdfha we=iquesta ugraveua ksid =reNj=kag yd isiqkag ta ka mszligyrKh myiq jQfha

ke fiuml kah Tn wg ma jkafka ta wjYHdj imqrdSug a Waidyhl msMhla

fi h

tneuacuteka fiuml kah u`ska foaYSh uacuteIhuddfotilde iSudjg hgaj ish ujqNdIdfjka wodlt uacuteIh

ikaOdrh mszligyrKh lsIacuteug isiqkag wjiadj iid we tfuka u uacuteuacuteO ka wsffrac34l mkas

jeks uQdYhjska wjYH fdr=re nd ekSu fjkqjg uacuteIhuddj u`ska wfmalaIs

fdr=re =reNj=kag yd isiqkag ksjerEgravej nd ekSug fiuml kah Wmldszlig jkq we

uacuteIh iiumlkaO uacutefYaI =reNj=ka yd uacuteYajuacuteoHd wdpdfrac34hjreka uacuteiska iiumlmdEgrave fiuml kah

cdsl wOHdmk wdhkfha uacuteIhud lntildegqfjka o wOHhk uKavfhka o mdl iNdfjka o

wkquesh nd Tn wg ma jk neuacuteka bylt mntildesfhka hq= nj ksfrac34foaY llt yels h

wdpdfrac34h ta atilde wfidal o isajd

wOHlaI

uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

v

wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr

wOHlaI ckrda cdsl wOHdmk wdhkh

weumllaIKh wdpdfrac34h ta auml ta o isajd

wOHlaI uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

uacuteIh kdhlajh tiuml tia uacuteluisxy

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh

wNHkar ixialrK uKavh ta fla jvqfa uhd

fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j

lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh

uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh (04 jk tallh)

ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh

fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh

uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j

wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07

iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv

vi

NdId ixialrKh

cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK

fala yjqia fldltU 10

uqa msgqj

wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh

uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd

(

vii

mgqk

wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii

wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv

uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v

04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27

11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02

12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05

121 jdhq kshu

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)

123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)

124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)

125 ujqsl mszligudj (Vm)

126 ixhqla jdhq ioacutelrKh

13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16

131 ujq Ndh wkqidrfhka wdxYsl mSvkh

14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18

141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk

142 pdl wKqljdofha ioacutelrKh

143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh

144 ueialafja-fndaaUumliaudka jHdmash

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23

151 jeka vrsquojdaia ioacutelrKh

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54

21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34

213 moaOshl =K

214 moaOshl wjiadj

215 tkaeamsh (H)

216 dmh

22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34

iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh

23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49

tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

1

wkafrac34 h

1 1 modfrac34fha wjiad =fkys wxY= ieleiau

iy tajdfha ofrac34YSh CIK

1 2 jdhquh wjiadj

1 2 1 jdhq kshu

bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq

ioacutelrKh

bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ

Kkh lsIacuteiuml

1 2 2 fndhsa kshuh

(mSvk-mszligud iiumlnkaOh)

1 2 3 pdaia kshuh

(WIaKajndashmszligud iiumlnkaOh)

1 2 4 wej dacircfrda kshuh

(mudK-mszligud iiumlnkaOh)

1 2 5 ujqsl mszligudj (Vm)

1 2 6 ixhqla jdhq ioacutelrKh

1 3 fvdaagkaf a wdxYsl mSvk kshuh

1 3 1 ujq Nd h wkqidrfhka

wdxYsl mSvkh

1 4 jdhq msltsn`o pdl wKql jdoh

1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla

i|yd Wmlamk

1 4 2 pdl wKql jdofha ioacutelrKh

1 4 3 jfrac34 uOHkH uQ fotilde h iy

uOHkH fotilde h

1 4 4 ueialafja--fndaaUumliaudka jHdmash

1 5 daauacutel jdhqjg eltfmk mszligEgrave

mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

1 5 1 jeka vrsquojdaia ioacutelrKh

1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

1 modfrac34fha jdhquh

wjiadj

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

v

wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr

wOHlaI ckrda cdsl wOHdmk wdhkh

weumllaIKh wdpdfrac34h ta auml ta o isajd

wOHlaI uacuteoHd fomdfrac34fiumlka=j

cdsl wOHdmk wdhkh

uacuteIh kdhlajh tiuml tia uacuteluisxy

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh

wNHkar ixialrK uKavh ta fla jvqfa uhd

fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd

iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j

lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh

uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh (04 jk tallh)

ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr

uacuteYajuacuteoHdh

fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh

uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j

wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07

iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv

vi

NdId ixialrKh

cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK

fala yjqia fldltU 10

uqa msgqj

wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh

uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd

(

vii

mgqk

wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii

wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv

uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v

04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27

11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02

12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05

121 jdhq kshu

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)

123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)

124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)

125 ujqsl mszligudj (Vm)

126 ixhqla jdhq ioacutelrKh

13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16

131 ujq Ndh wkqidrfhka wdxYsl mSvkh

14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18

141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk

142 pdl wKqljdofha ioacutelrKh

143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh

144 ueialafja-fndaaUumliaudka jHdmash

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23

151 jeka vrsquojdaia ioacutelrKh

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54

21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34

213 moaOshl =K

214 moaOshl wjiadj

215 tkaeamsh (H)

216 dmh

22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34

iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh

23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49

tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

1

wkafrac34 h

1 1 modfrac34fha wjiad =fkys wxY= ieleiau

iy tajdfha ofrac34YSh CIK

1 2 jdhquh wjiadj

1 2 1 jdhq kshu

bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq

ioacutelrKh

bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ

Kkh lsIacuteiuml

1 2 2 fndhsa kshuh

(mSvk-mszligud iiumlnkaOh)

1 2 3 pdaia kshuh

(WIaKajndashmszligud iiumlnkaOh)

1 2 4 wej dacircfrda kshuh

(mudK-mszligud iiumlnkaOh)

1 2 5 ujqsl mszligudj (Vm)

1 2 6 ixhqla jdhq ioacutelrKh

1 3 fvdaagkaf a wdxYsl mSvk kshuh

1 3 1 ujq Nd h wkqidrfhka

wdxYsl mSvkh

1 4 jdhq msltsn`o pdl wKql jdoh

1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla

i|yd Wmlamk

1 4 2 pdl wKql jdofha ioacutelrKh

1 4 3 jfrac34 uOHkH uQ fotilde h iy

uOHkH fotilde h

1 4 4 ueialafja--fndaaUumliaudka jHdmash

1 5 daauacutel jdhqjg eltfmk mszligEgrave

mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

1 5 1 jeka vrsquojdaia ioacutelrKh

1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

1 modfrac34fha jdhquh

wjiadj

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

vi

NdId ixialrKh

cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK

fala yjqia fldltU 10

uqa msgqj

wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh

uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd

(

vii

mgqk

wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii

wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv

uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v

04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27

11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02

12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05

121 jdhq kshu

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)

123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)

124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)

125 ujqsl mszligudj (Vm)

126 ixhqla jdhq ioacutelrKh

13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16

131 ujq Ndh wkqidrfhka wdxYsl mSvkh

14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18

141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk

142 pdl wKqljdofha ioacutelrKh

143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh

144 ueialafja-fndaaUumliaudka jHdmash

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23

151 jeka vrsquojdaia ioacutelrKh

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54

21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34

213 moaOshl =K

214 moaOshl wjiadj

215 tkaeamsh (H)

216 dmh

22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34

iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh

23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49

tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

1

wkafrac34 h

1 1 modfrac34fha wjiad =fkys wxY= ieleiau

iy tajdfha ofrac34YSh CIK

1 2 jdhquh wjiadj

1 2 1 jdhq kshu

bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq

ioacutelrKh

bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ

Kkh lsIacuteiuml

1 2 2 fndhsa kshuh

(mSvk-mszligud iiumlnkaOh)

1 2 3 pdaia kshuh

(WIaKajndashmszligud iiumlnkaOh)

1 2 4 wej dacircfrda kshuh

(mudK-mszligud iiumlnkaOh)

1 2 5 ujqsl mszligudj (Vm)

1 2 6 ixhqla jdhq ioacutelrKh

1 3 fvdaagkaf a wdxYsl mSvk kshuh

1 3 1 ujq Nd h wkqidrfhka

wdxYsl mSvkh

1 4 jdhq msltsn`o pdl wKql jdoh

1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla

i|yd Wmlamk

1 4 2 pdl wKql jdofha ioacutelrKh

1 4 3 jfrac34 uOHkH uQ fotilde h iy

uOHkH fotilde h

1 4 4 ueialafja--fndaaUumliaudka jHdmash

1 5 daauacutel jdhqjg eltfmk mszligEgrave

mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

1 5 1 jeka vrsquojdaia ioacutelrKh

1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

1 modfrac34fha jdhquh

wjiadj

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

vii

mgqk

wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii

wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv

uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v

04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27

11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02

12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05

121 jdhq kshu

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)

123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)

124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)

125 ujqsl mszligudj (Vm)

126 ixhqla jdhq ioacutelrKh

13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16

131 ujq Ndh wkqidrfhka wdxYsl mSvkh

14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18

141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk

142 pdl wKqljdofha ioacutelrKh

143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh

144 ueialafja-fndaaUumliaudka jHdmash

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23

151 jeka vrsquojdaia ioacutelrKh

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54

21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34

213 moaOshl =K

214 moaOshl wjiadj

215 tkaeamsh (H)

216 dmh

22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34

iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh

23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49

tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

1

wkafrac34 h

1 1 modfrac34fha wjiad =fkys wxY= ieleiau

iy tajdfha ofrac34YSh CIK

1 2 jdhquh wjiadj

1 2 1 jdhq kshu

bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq

ioacutelrKh

bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ

Kkh lsIacuteiuml

1 2 2 fndhsa kshuh

(mSvk-mszligud iiumlnkaOh)

1 2 3 pdaia kshuh

(WIaKajndashmszligud iiumlnkaOh)

1 2 4 wej dacircfrda kshuh

(mudK-mszligud iiumlnkaOh)

1 2 5 ujqsl mszligudj (Vm)

1 2 6 ixhqla jdhq ioacutelrKh

1 3 fvdaagkaf a wdxYsl mSvk kshuh

1 3 1 ujq Nd h wkqidrfhka

wdxYsl mSvkh

1 4 jdhq msltsn`o pdl wKql jdoh

1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla

i|yd Wmlamk

1 4 2 pdl wKql jdofha ioacutelrKh

1 4 3 jfrac34 uOHkH uQ fotilde h iy

uOHkH fotilde h

1 4 4 ueialafja--fndaaUumliaudka jHdmash

1 5 daauacutel jdhqjg eltfmk mszligEgrave

mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

1 5 1 jeka vrsquojdaia ioacutelrKh

1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

1 modfrac34fha jdhquh

wjiadj

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

1

wkafrac34 h

1 1 modfrac34fha wjiad =fkys wxY= ieleiau

iy tajdfha ofrac34YSh CIK

1 2 jdhquh wjiadj

1 2 1 jdhq kshu

bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq

ioacutelrKh

bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ

Kkh lsIacuteiuml

1 2 2 fndhsa kshuh

(mSvk-mszligud iiumlnkaOh)

1 2 3 pdaia kshuh

(WIaKajndashmszligud iiumlnkaOh)

1 2 4 wej dacircfrda kshuh

(mudK-mszligud iiumlnkaOh)

1 2 5 ujqsl mszligudj (Vm)

1 2 6 ixhqla jdhq ioacutelrKh

1 3 fvdaagkaf a wdxYsl mSvk kshuh

1 3 1 ujq Nd h wkqidrfhka

wdxYsl mSvkh

1 4 jdhq msltsn`o pdl wKql jdoh

1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla

i|yd Wmlamk

1 4 2 pdl wKql jdofha ioacutelrKh

1 4 3 jfrac34 uOHkH uQ fotilde h iy

uOHkH fotilde h

1 4 4 ueialafja--fndaaUumliaudka jHdmash

1 5 daauacutel jdhqjg eltfmk mszligEgrave

mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

1 5 1 jeka vrsquojdaia ioacutelrKh

1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

1 modfrac34fha jdhquh

wjiadj

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

2

ye|skaugraveu

uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j

mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk

uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama

lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels

^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel

ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO

wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl

wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml

ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq

h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka

ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj

oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr

wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug

bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu

fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u

mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde

11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK

wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h

wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd

jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka

wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml

suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde

mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa

lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h

gtk

^Wod( hlv weKhamp

iaOacuter yevhla yd

mszligudjla we

oslashj

^Wod( champ

iaOacuter yevhla

kes kuqa iaOacuter mszligudjla we

jdhq

^Wod( ySshiuml neAEligkamp

iaOacuter yevhla fyda

iaOacuter mszligudjla fyda ke

gtk

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n mn h

wxY= liumlmkh jk kuqa

eklska eklg

pkh fkd fotilde

oslashj

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n triuml

mn fkd fotilde wxY=jg hiuml

mudKhlg eklska eklg

pkh uacuteh yels h

jdhq

wxY= ^mrudKq wKq fyda whkamp

wr wdlfrac34IK n yumln h

wxY=jg eklska eklg

pkh uacuteh yels h

11 rEmh modfrac34fha suacuteO wjiad

wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde

wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq

wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

3

sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh

yelafla gtk wjiadfotilde muΠoslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq

fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde

wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj

wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave

modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks

ufyaalaI =Kj fjkialiumljg =vq fohs

1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh

=Kh gtk oslashj jdhq

yevh ksYaNtilde h wvx = n`yumlfkys

yevh kakd uqa

n`yumlfkys uq`M mszligudj

mqrd fkd mesfrhs

n`yumlfkys yevh

kakd wr

n`yumlfkys iuia

mszligudj wa lr kS

mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys

mszligudj wa lr kS

gtkajh (ρ) g cm-3 (293 K sect)

bylt w hka kS

Wod( hlv

(7 874 g cm-3)

rula bylt w hka

kS

Wod( ch

(0 997 g cm-3)

w hka mylt h

Wod( yhsvcka

(0 071g cm-3)

iiumlmSvHdj iiumlmSvkh lsIacuteu

bd yumlIalr h

iiumlmSvkh lsIacuteu bd

yumlIalr h

fnfyuacuteka iiumlmSvkh

llt yels h

igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka

ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha

n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o

c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk

wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska

oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh

u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha

yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj

o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk

wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh

fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml

ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka

fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh

kS

ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh

llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml

ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk

wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde

WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys

wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

4

12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh

11 ksoiqk

wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha

ljr kiuml wjiadfotilde o

uacutei`yumlu oslashj wjiadj

11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu

yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj

pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj

iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka

th wxY=j pkh fyda dmc psh i`oyd fya= fotilde

wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua

okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj

modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash

wr iu=sfhys msMhla fi ielsh yels h

wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp

wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg

bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla

jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc

Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka

meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc

Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

5

13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad

=fkys yeisIacuteu

modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm

modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga

ild nuq

12 jdhquh wjiadj

oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj

yeisIacuteu flfrys wjOdkh fhduq lruq

11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar

flffrac34

bull jdhq bd iiumlmSvH fotilde

bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs

bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we

bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj

kS

bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl

iuOtilde ntildeY fotilde

jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha

yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh

yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj

WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH

wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl

ugrave we

121 jdhq kshu

wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K

mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy

jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

6

modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla

mldY fotilde

mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh

jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K

jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda

n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl

mszligudj fkdild yeszligh yels h

jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp

jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my

mldYkfhka ksrEmKh flffrac34

fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu

jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd

mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi

y`yumlkajkq efiacute

fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h

my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj

22 414 dm3 fotilde)

mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk

wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi

o ye|skafotilde

mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml

mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk

tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd

uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u

tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk

mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h

idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml

eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we

12 j =j mSvkh i`oyd jk tall

mSvk tallh Pa bar atm torr mmHg

1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3

1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

7

12 ksoiqk

jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj

fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh

hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde

(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh

ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o

(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)

(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak

(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak

uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak

WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3

n fkdokakd moh fotilde

PV = nRT Nduacutefhka

(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1

fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g

(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3

by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj

fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh

iy gtkajh fiuacuteh yels h

PV = nRT

P = RT

zwnjzwnj P = CRT

fuys zC Zhkq idkaoslashKhhs

j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h

PV = RT

fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs

P = RT fi o suacuteh yels h

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

8

gtkajh (d) =

there4 P =

uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl

moku fi lshd lrhs

122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg

msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk

fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia

jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ

frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh

my oelafotilde

my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod

yelsh PV= nRT

jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh

kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde

PV = k (kshhla)

tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla

fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls

ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2

mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj

14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34

14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we

k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek

o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde

midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh

uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

9

1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde

mSvkfha fjkia ugraveu

14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk

ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr

u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o

jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla

=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde

igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka

fok nj wms oksuq tuksid ksh WIaKajfhasect

hkqfjka suacuteh yels h

1 3 ksoiqk

ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg

mSvkfha isyuml jk fjkia ugraveu Kkh lrkak

uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

10

1 4 ksoiqk

ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh

mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u

we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o

uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2

100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h

123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave

ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`

jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia

wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we

0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg

fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg

wkqj

t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr

0 degC i`oyd T0 = 273 15 uOtildeska nd fohs

fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj

mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk

wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde

fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

11

tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg

wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde

jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys

WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg

yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h

PV = nRTV = nRT P

ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde

zwnjzwnjzwnjzwnjV prop T fyda V = kT

pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka

WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd

Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect

ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh

lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34

15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde

uacutepkh

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

12

1 5 ksoiqk

ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml

jk WIaKaj fjki Kkh lrkak

uacutei`yumlu

T1 = T V1 = V V2 = 3V T2 =

T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh

wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h

hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi

efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg

lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr

kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde

1 6 ksoiqk

23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde

tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki

Kkh lrkak

uacutei`yumlu

T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =

jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka

V2 = 2 03 dm3

mszligudfotilde isyumljk fjki = 0 03 dm3

124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=

jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj

lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla

hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)

fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

13

jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda

kshh (NA fyda L) fi ye|skafotilde

my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka

wjfndaO lr yels h

fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl

u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud

follg by iiumlnkaOdj fhsectfuka

P iy T ksh uacuteg sect (R iy NA kshhka fotilde )

irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud

=lt iudk wKq ixLdjla wvx= fotilde (V α N)

by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd

mszligmQfrac34K jdhq ioacutelrKh nd yels h

by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka

k = R jQ uacuteg

P V = n R T

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

14

125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka

fi wmg suacuteh yels h

iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd

mszligudj (Vm) tl u w hla uacuteh hq= ksid th

fi Kkh llt yels h

tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u

mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34

bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu

aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj

22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi

ksrEmKh flffrac34

bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde

fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde

igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde

V = k n = k (m M) tneuacuteka M = k (m V) = k d

1 7 ksoiqk

298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud

iudk nj fmkajkak

uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe

VHe = nHeRTHe PHe

VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

15

PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =

PNeVNe = nNeRTNe

VNe = nNeRTNe PNe

VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa

VNe = 24 4 dm3

tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq

wa lr kakd mszligud iudk fotilde

126 ixhqla jdhq kshuh

jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj

tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka

T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla

fi suacuteh yels h

fuh ixhqla jdhq kshuh fi ye|skafotilde

1 8 ksoiqk

25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o

uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh

P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3

T1 = 25 + 273 = 298 K

V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =

P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

16

13 fvdaagkaf a wdxYsl mSvk kshuh

fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm

yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk

wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml

ishuml jdhq odhl fotilde

jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj

wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde

ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla

iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs

fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh

fi yeEgravekafotilde

A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska

PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde

my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka

jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha

we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh

PT hehs o isuq

PV = nRT

A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )

B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )

jdhq ntildeYKh i`oyd nT = PTV RT

iy nT = nA + nB

tu ksid PTV RT = (PAV RT) + (PBV RT)

iq`M llt uacuteg PT = PA + PB

fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl

131 ujq Nd h wkqidrfhka wdxYsl mSvkh

T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq

ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde

fvdaagkaf a kshuhg wkqj PT = PA + PB

PA iy PB mldYk fjk fjk u PT jska fnsectfuka

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

17

tu ksid

fi suacuteh yels h

hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk

fotilde

1 9 ksoiqk

(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla

tla jdhqfotilde wdxYsl mSvkh Kkh lrkak

(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd

lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq

ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak

uacutei`yumlu

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

18

fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK

u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd

fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj

tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla

fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re

uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq

irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq

efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj

u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk

nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja

ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj

mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=

jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes

lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect

tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh

wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K

jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl

1 10 ksoiqk

my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs

iskak

2KClO3(s) rarr2KCl(s) + 3O2(g)

27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute

27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh

Kkh lrkak

uacutei`yumlu

fvdaagkaf a kshuhg wkqj

Piuia = PTlaiscka + Pch

PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa

mszligmQfrac34K jdhq ioacutelrKh fhsectfuka

14 jdhq msltsn`o pdl wKqljdoh

by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(

fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks

mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla

nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka

uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml

jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh

llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad

fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd

fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj

yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

19

141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde

wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd

uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr

wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS

wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh

u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka

gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska

jdhqj bylt iiumlmSvHdj meyeEgraves fotilde

bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu

jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO

wKqjg uacuteuacuteO fotilde mjS

fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg

ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash

jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk

ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde

bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS

fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq

wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj

fuu ska mldY flffrac34

fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh

mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt

uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka

jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr

iiumlnkaOdjh my ioacutelrKfhka nd foa

jyumlrga my oelafjk lreKq plusmnlauacuteh yels h

bull jdhq wxY= tlsfklska iajdhaj yeisffrac34

jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska

iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda

fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj

wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml

Wmlamkfhka meyeEgraves fotilde

bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla

u` ska mSvkhla wes fotilde

fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect

ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl

isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

20

fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml

jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq

ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj

jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml

fotilde

142 pdl wKqljdofha ioacutelrKh

my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla

fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34

by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes

wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka

wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34

uOHkH fotilde h fi wfrac34 olajkq efiacute

143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h

my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu

jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg

jfrac34 uOHkH uQ fotilde h fotilde

jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla

jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=

Kkla i`oyd ioacutelrKh ild nuq

N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)

PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

21

tu ksid jfrac34 uOHkH uQ fotilde h

fi suacuteh yels h

1 11 ksoiqk

25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak

uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1

by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj

fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama

lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml

pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh

u` ska th my oelafjk mszligEgrave idOkh llt yels h

fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt

yel

kB hkq fndaaUumliaudka kshh fotilde

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

22

wKqjla i`oyd

ujqhla i`oyd

fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq

fotilde

144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml

N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag

pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq

efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave

mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes

lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde

jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash

fi ye|skafotilde

16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--

fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd

fotilde jHdmash

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

23

15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh

fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka

wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea

jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd

idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute

ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr

^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17

rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla

i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34

17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj

iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha

sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka

daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh

17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd

Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir

ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla

mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy

ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh

yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr

jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml

ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej

jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla

fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh

fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs

17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska

o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska

daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka

iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk

wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh

hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd

mszligudj (V)

mSvk

h (

P)

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

24

jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj

o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga

meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg

jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke

fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka

lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS

jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru

ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml

yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj

sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK

n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde

mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd

laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect

(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g

jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda

ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel

jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt

WIaKaj fotilde

daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o

WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel

fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg

jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml

fuh mltuq ioacutelrKfha wdfoaYfhka

fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH

ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk

nj wmg fmfka

fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh

pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we

tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj

hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h

mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq

wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt

jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect

jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia

PV mszligmQfrac34K

daauacutel

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

25

jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq

wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka

yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=

h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka

wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel

jdhq mszligmQfrac34K aajfhka wm ukh fotilde

151 jeka vrsquo jdaia ioacutelrKh

fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa

sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K

jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk

wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq

mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel

jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid

daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH

fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj

iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk

Egrave

bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka

kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka

mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka

igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash

iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg

fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh

mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde

1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj

ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh

by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK

fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde

gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq

mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde

fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg

iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq

msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect

moaOsfha mSvkh my mldYkfhka nd fohs

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

26

bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL

fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr

tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk

mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka

wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks

fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq

kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh

fi kej suacuteh yels h

fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh

fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde

152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu

fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql

nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia

flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha

wkafrac34--mszligjfrac34kh l yels fotilde

ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs

wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj

yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde

igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys

sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde

ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha

lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh

iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla

fi o yeisszligh yels ugraveu h

bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla

oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi

mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS

30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc

oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi

muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu

WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla

oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde

( )2

aP V b RTV

+ minus =

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

27

19 rEmh CO2 j ldm igyk

1 3 j =j - ioacutelrK idrdxYh

jdhq kshuh intildelrKhksh j mjsk

idOl

mszligmQfrac34K jdhq kshuh PV = nRT ke

fndhsa kshuh n iy T

pdaia kshuh V = kT n iy P

wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T

wKql pdl ioacutelrKh

idudkH fotilde h

jfrac34 uOHkH fotilde h

jfrac34 uOHkH fotilde h

fvdaagkaf a wdxYsl mSvk

kshuh

PA = xA PT

PT = PA + PB + PC

iiumlmSvHd idOlh jdhq ujq 1la i|yd

jeka vZjdaia ioacutelrKh

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

28

wkafrac34 h

21 dm-ridhksl uacuteoHdfotilde yd

dms uacuteoHdfotilde uQsl mo

211 moaOsh jgmsgdj yd iSudj

212 moaOs jfrac34

bull uacutejD moaOs

bull ixjD moaOs

bull tals moaOs

bull iucdsh yd uacuteIucdSh moaOs

213 moaOshl =K

bull wkaugravelaISh =K

bull ufyalaI =K

bull uacuteas =K

bull gtgkd =K

214 moaOshl wjiadj

bull iajhxisoaO lshdjsh

bull iajhxisoaO fkdjk lshdjs

bull msjfrac34H lshdjsh

bull wmsjfrac34H lshdjsh

215 tkaeamsh (H)

216 dmh

bull uacuteYsIag dm Odszligdj iy dm

Odszligdj

22 uacuteuacuteO dm-ridhksl lshdjs$

mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

221 dmodhl yd dmdjfYdaIl lshdjs

bull iiumlu tkaeams uacutemfrac34hdi

222 dm-ridhksl ioacutelrK

223 tkaeams rEmigyka

224 tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

bull iiumlu Wamdok tkaeamsh ΔHθf

bull iiumlu oyk tkaeamsh ΔHθC

bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD

bull iiumlu WodiSkslrK tkaeamsh ΔHθneu

bull iiumlu ioslashdjK tkaeamsh ΔHθsol

bull iiumlu ick tkaeamsh ΔHθhyd

bull iiumlu oslashdjK tkaeamsh ΔHθdissolution

bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub

bull iiumlu jdIamSlrK tkaeamsh ΔHθevap

bull iiumlu uacutehk tkaeamsh ΔHθfus

bull iiumlu mrudKqlrK tkaeamsh ΔHθat

bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ

IE1

bull iiumlu bflafgdaklrK tkaeamsh ΔHθ

EG

whksl ixfhdahl iiumlu oesia

(uacutegtgk) tkaeamsh ΔHθL

225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams

23 oesia tkaeamsh fyja whksl

ixfhdahl Wamdok tkaeamsh (

fndaka-ydnfrac34 plh

24 ridhksl mslshdj iajhxisoaOdj

bull ridhksl mslshdjl iiumlu

tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd

iajhxisoaOdj

2 Ylas uacuteoHdj

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

29

ye|skaugraveu

fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda

uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu

jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre

ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d

hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla

woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla

fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk

uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi

msltsn`o wOHhkhhs

fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk

fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj

wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy

iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO

ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu

wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml

i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka

tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq

2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo

2 1 1 moaOsh jgmsgdj yd iSudj

dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute

flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h

bull moaOsh

fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda

uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj

fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp

bull jgmsgdj

moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq

isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp

bull iSudj

moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas

iSudj fi ielsh yel)

2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

30

212 moaOs jfrac34

moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl

moaOs wfrac34 oelauacuteh yels h

bull uacutejD moaOs

Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels

moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla

wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk

fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka

jgmsgdjg neyer lsIacuteuga yels h

bull ixjD moaOs

iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd

yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd

nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml

i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla

lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp

thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h

bull tals moaOs

Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs

tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq

igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs

2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh

bull iucdSh yd uacuteIucdSh moaOs

moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg

iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska

hqa ntildeYKhla oacuteg ksoiqka fotilde

moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde

kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde

iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml

i|yd ksoiqka fotilde

2 1 3 moaOshl =K

bull wkaugravelaISh =K

moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls

tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl

Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg

ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

31

bull ufyalaI =K

moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml

fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh

jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde

moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h

bull uacuteas =K

moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde

mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka

fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta

fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk

fotilde tkiuml ialkaOh uacuteas =Khls

bull gtgkd =K

moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde

moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh

wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh

u oS fkd mjS

lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma

fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh

ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde

2 1 4 moaOshl wjiadj

moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl

wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh

(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj

wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj

moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde

moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha

wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs

moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk

wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h

moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda

namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj

fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad

Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh

u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh

yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla

njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu

i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek

isagraveu mudKja h

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

32

iiumlu wjiadj

moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja

lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok

o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls

IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34

olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde

WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys

wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO

hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq

miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd

wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla

bull iajhxisoaO lshdjsh

iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml

flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks

lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla

iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla

iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde

bull iajhxisoaO fkdjk lshdjs

iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj

moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka

jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska

dmh iemfhk fla jdfha nd wes ldnka sks fkd kS

bull msjfrac34H lshdjsh

msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh

lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka

u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl

wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd

fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk

tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa

moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi

whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm

mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h

bull wmsjfrac34H lshdjsh

wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh

hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs

iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H

lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls

2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk

aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka

jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak

fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa

isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq

msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka

ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

33

u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka

tkaeams fjki ΔH h

mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr

fjkihs

2 1 6 dmh

ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml

ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq

nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod

ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj

msltsn`o wjfndaOhla nd hq= h

uacuteYsIag dm Odszligdj iy dm Odszligdj

hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh

fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj

(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug

wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas

=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(

fuys m - oslashjHfha ialkaOh ^ aiumljskaamp

igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde

ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml

ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1

igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd

tallh J degC-1 ^fyda J K-1) fotilde

hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki

Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm

mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h

fuys m = idiumlmfha ialkaOh

Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl

q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd

q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

34

2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd

iiumlu tkaeams uacutemfrac34hdi

ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh

fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki

moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h

2 2 1 dmodhl yd dmdjfYdaIl lshdjs

dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia

lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl

fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg

fjka llt yels h

2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu

dmdjfYdaIl mslshd dmodhl mslshd

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh

jk lshdjs dmdjfYdaIl lshdjs fotilde

wdriumlNl wjiadfjka wjika wjiadjg

mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh

jk lshdjs dmodhl lshdjs fotilde

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd jeauml h wjYH wur Ylash

moaOsh uacuteiska dmh fi jgmsgdfjka

wjfYdaIKh lr kq efiacute

Wod( wefudakshiuml lafdarhsacirc cfha

EgravehlsIacuteu

moaOsfha wjika wjiadfotilde sect Ylash

tys wdriumlNl wjiadfotilde sect Ylashg

jvd wvq h wur Ylash dmh fi

jgmsgdjg ksoyia fotilde

Wod( ishuml oyk lshdjs dmodhl h

idudkHfhka dmdjfYdaIl fNsl

mszligjfrac34khl sect wdriumlNl wjiadj

wjika wjiadj fj f k tau i`oyd

dmh iemhsh hq=h

Wod( dmh iemhSfuka gtkhla oslashj njg

ma lsIacuteu dmdjfYdaIl lshdjshls

fNsl mszligjfrac34kh dmodhl kiuml

wdriumlNl wjiadj wjika wjiadj fj

f k tau i`oyd dmh bja llt hq= h

Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu

dmodhl lshdjshls

mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp

moaOsh uacuteiska jgmsgdfjka dmh

wjfYdaIKh lr kakd dmdjfYdaIl

lshdjshl ΔH Ok fotilde

^tkiuml ΔH gt O fotildeamp

moaOsh uacuteiska jgmsgdjg dmh ksoyia

lrk dmodhl lshdjshl ΔH RK

fotilde

^tkiuml ΔH lt O fotildeamp

2 21 1N (g) O (g) 90 kJ NO(g)2 2

+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2

+ rarr

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

35

tk

ae

amsh

M

ΔH gt 0

mslshl

tk

ae

amsh

M

ΔH lt 0

mslshl

ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki

oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams

fjki flltska u uek yels h

iiumlu tkaeams uacutemfrac34hdi

mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl

wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs

mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34

olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh

fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska

ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk

kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th

tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys

i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde

irj lsjfyda

mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect

mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml

jk tkaeams uacutemfrac34hdihhsiexcl

2 2 2 dm--ridhksl ioacutelrK

Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl

ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla

sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka

(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd

Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde

(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd

Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS

tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h

(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh

fkdfjkiaj mjS

(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj

fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj

oelaugraveu wHjYH fotilde

(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml

tkaeams fjki o tu ixLHdfjka u =K llt hq= h

(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys

il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

36

ksoiqkmy oelafjk mslshd ilkak

2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1

2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1

by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h

bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde

bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde

bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde

iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams

fjki fldmuK o hkak bEgraveszligma flffrac34

igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka

jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla

ksoyia jk njhs

iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ

igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg

483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde

by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ

ksoiqkla fi( my mslshdj iluq

4H2(g) + 2O2 (g) rarr 4H2O(g)

fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute

tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h

mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg

tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml

tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h

tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ

wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde

wm my wdldrhg ioacutelrK shQ uacuteg

tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka

idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by

ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr

fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

37

yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs

bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau

aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o

jx = h

2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1

2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1

2 2 3 tkaeams rEmigyka

my oelafjk mslshdj ilkak

C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1

by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh

mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg

ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde

N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1

by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we

fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka

mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk

tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka

u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys

oelafotilde

2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams

rEmigyka

2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi

iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf

oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla

iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

38

sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm

hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u

iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj

o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml

flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk

neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde

ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod

kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h

Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)

ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg

wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta

fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd

Y+kH w h mejszligh fkdyels h

C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1

iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka

hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute

25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok

mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h

by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak

fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq

my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa

jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs

298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml

lreK my oelafjk ioacutelrKfhka mldY fotilde

ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu

tkaeams lsysmhla wfrac34 olajd sicircu jagrave

iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC

iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde

wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu

wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh

fotilde

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1

C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

39

iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD

tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu

wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams

uacutemfrac34hdihhs

H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1

CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1

CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1

CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1

CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1

tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh

wh fotilde

CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih

= 416 75 kJ mol-1

iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu

tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla

mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs

H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1

iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde

1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Mn+(g) + solventrarr Mn+(solvent)

iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd

tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave

1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs

Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1

iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution

tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3

oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1

iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda

ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml

jk tkaeams uacutemfrac34hdihhs

Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1

iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap

tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde

wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

40

iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus

tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg

mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1

iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat

tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq

ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1

iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1

tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg

jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh

tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1

iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG

tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh

lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ

EG = -349 kJ mol-1

tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde

whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL

tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh

Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs

NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1

2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh

tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml

ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt

yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml

yelshdj eicirc we

ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)

Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq

N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1

NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ

w h foflka fnouq

wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka

by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde

fyia dm iudlk kshuh i`oyd ksoiqkla(

N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh

ksfrac34Kh lsIacuteu msltsn`o ild nuq

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

41

Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd

O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg

wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg

wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute

________________________________________________________

by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde

lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml

iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams

uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys

msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk

udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk

o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h

my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl

plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde

2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels

udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr

follska flfrk mszligjfrac34kh

2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu

tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams

uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys

mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

42

Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg

jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh

flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma

flfrk udfrac34 fol mldYs h

2 5 rEmh dm--ridhksl plh

dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl

mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH

ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave

dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh

Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka

rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq

jk B fkduacuteh hq= h

oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka

=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha

(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka

mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt

hq= nj ul nd kak (my ksoiqk nkak)

ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs

isuq

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =

oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka

yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk

wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk

wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh

llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh

lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh

fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs

fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl

ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o

mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

43

sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj

ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h

C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)

(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime

blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK

we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde

3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect

we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=

lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h

3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime

3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1

dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h

ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1

tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h

wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul

w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels

fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka

we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u

Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

44

2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk

(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg

wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams

mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg

wkqj wmg il=K SrKh llt yels h

iiumlu mslshd tkaeams

mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu

tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34

iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams

Kkh lsIacuteuhs

ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk

mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk

wdldrh uacuteuid nuq

2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

45

mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd

yel

________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ

rxn =

(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau

ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs

(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla

Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY

llt yels h

tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga

tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk

wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h

fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq

mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq

2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34

sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq

mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ

f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]

mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ

f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ

f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ

f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

46

tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka

iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave

iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu

tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu

tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI

Nduacutehls

fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde

Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde

tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ

r fi o ye`Egravekafotilde) efiacute

ir ksoiqkla fi my oelafjk lams mslshdj ilkak

a A + b B rarr c C + d D ΔHθrxn =

fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk

ioacutelrKfhka fokq efiacute

ΔHθrxn = [c ΔHθ

f [C] + d ΔHθf [D] ] ndash [ a ΔHθ

f [A] + b ΔHθf [B] ]

Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk

oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl

luh Nduacutehg yels h

Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ

f ksfrac34Kh lsIacuteu

i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs

isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj

ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h

ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rwjYH mslshdj jkafka

jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels

h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml

ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by

uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh

llt yels h

^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

47

ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ

rxn Kkh lrkak

mslts=rfuh Tng yuq jk fyia plj mfhdackhls

my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu

i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute

C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh

C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk

ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34

2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh

whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl

ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash

yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd

h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde

tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI

legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls

tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr

wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u

fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg

iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h

oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl

jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi

Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr

=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj

iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka

wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

48

fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave

weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml

jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh

i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr

mslshdj ilkak

ΔHθrxn =

fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu

Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my

uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh

Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh

lsIacuteug fuu luh fhdod yel

1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu

2 F2(g) F(g) njg mrudKqlrKh lsIacuteu

3 jdhquh sshiuml mrudKq whkSlrKh ugraveu

4 bflafgdak ms yKh lr F- iEsectu

5 Li+(g) yd F-(g) ixfhdackh ugraveu

LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks

ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h

iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg

fufia suacuteh yels h

ΔHθrxn = ΔHθ

1 + ΔHθ2 + ΔHθ

3 + ΔHθ4 + ΔHθ

5

by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute

tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ

5

ΔHθ5 = -1016 6 kJ mol-1 fotilde

tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde

-1753 kJ mol

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

49

my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde

1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash

uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd

Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja

u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka

lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd

nj ul nd kak

2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h

-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh

1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml

flfrk wr (b) rEmh tajd fjka fjkaj olajhs

2 4 ridhksl mslshdj iajhxisoaOdj

iajhxisoaO lshdjs

mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh

msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia

kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml

iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO

mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla

woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34

oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug

fyda yels h j o th fldfya u isyuml fkdugraveug o yels h

ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg

mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th

isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h

dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg

mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml

fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak

ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

50

ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd

fotilde

fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm

mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=

h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh

(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad

Yshls tys tallh J K-1 mol-1 fotilde

fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl

Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd

WIaKajh ek muKla ild nefa

jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug

keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla

oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka

vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U

fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK

ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h

ridhksl mslshdjl iiumlu tkafgdms fjki

mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl

tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh

lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha

iafgdhslsfhdntildesl ix =Kljska =K flffrac34

ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH

ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde

iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka

lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula

fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd

bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl

ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde

ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs

2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ

rxn

Kkh lrkak

- rxnS S S∆ = sum sum^Mamp ^mslshlamp

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

51

mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd

ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq

ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h

iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg

ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)

= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ

[H2(g)]) + (1 mol)(ΔSθ [O2(g)])

= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1

fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml

lr fk isyuml l fmrhSu iuOtilde efma

mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd

tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi

wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg

yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj

aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag

ekSu wjYH h

ΔHθrxn (-) ΔSθ

rxn (+) ishuml WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (+) bylt WIaKajj sect iajhxisoaO h

ΔHθrxn (-) ΔSθ

rxn (-) mylt WIaKajj sect iajhxisoaO h

ΔHθrxn (+) ΔSθ

rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde

^wdmiq mslshdj iajhxisoaO hamp

siacuteia fhdacH Ylash (G) yd iajhxisoaOdj

wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams

fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik

mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad

Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde

ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia

wfrac34 oelafotilde

ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas

fjki my ioacutelrKfhka mldYs h

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

52

igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ

r hkako Nduacuted fotilde

bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq

EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl

ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo

rxn gt 0 fotilde

ksoiqk 25

ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)

ΔHθrxn yd ΔSθ

rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas

fjki Kkh lrkak

(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ

f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)

mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde

tkaeams fjki Kkh lrkak

ΔHθrxn = ΔHθ

f (M) minus ΔHθf (msslshl)

= ΔHθf [CO2(g)] minus ΔHθ

f [CO(g)] minus frac12 ΔHθf [O2(g)]

= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1

= minus2830 kJ mol-1

iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde

tkafgdms fjki Kkh lrkak

ΔSθrxn = Sθ (M) minus Sθ (msslshl)

= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1

igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka

lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks

my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn

= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1

ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

53

2 2 j =j( ioacutelrKj idrdxYh

ioacutelrK tall

mslshdjl

tkaeams fjki

ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1

mslshdjl iiumlu

tkaeams fjki

(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)

kJ mol-1

fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka

^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh

i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj

tkaeams uacutemfrac34hdij tl=jg iudk fotilde

wka whqszligka lsj fyda fyia kshuh tkaeamsfhys

wjiad Ys =Kfhys msMhls wdriumlNl

wjiadfotilde isg wjika wjiadj fj tltocircfha

l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh

iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd

weafa tl u w hla jk wr th udfrac34 fhka

iajdha h

mslshdjl iiumlu

tkafgdms fjki

ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1

mslshdjl iiumlu

siacuteia fhdacH Ylas

fjki

ΔGθrxn = ΔHθ

rxn ndash T ΔSθrxn kJ mol-1

mslshdjl

iajhxisoaOdj

ieu WIaKajhl sect u

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

bylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (+) ΔSθ

rxn (+)

mylt WIaKajj sect

iajhxisoaO ΔHθ

rxn (ndash) ΔSθ

rxn (ndash)

ieu WIaKajhlsectu

iajhxisoaO fkdjk

(msjfrac34H mslshdj

iajhxisoaO fotildeiexcl)

ΔHθrxn (+)

ΔSθrxn (ndash)

iajhxisoaO ΔGθrxn lt 0

iajhxisoaO fkdjk ΔGθrxn gt 0

iu=s ΔGθrxn = 0

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill

54

mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford

University Press

Chang R (2010) Chemistry 10th Edition New York McGraw Hill