notes on states of matter

8/20/2019 Notes on States of Matter

1/101

CHEM 155 Basic Physical Chemistry(2, 1, 2)

1

Introduction to Physical Chemistry: Defnition,Structure o Science, Classifcations; Laws,y!otheses, "heories an# $o#els%

States of Matter I& Classifcation; Structure an#Pro!erties o matter; "y!es o systems; State 'arialesan# *uations o state%

Thermodynamics I& "he +irst law, eat Ca!acity,nthal!y an# "hermochemistry%

Chemical Kinetics I& lementary Chemical -inetics,Basic Laws, .ect o "em!erature an# the /rrheniuse*uation%


2/101

MATTE

States o $atter, Structure (the waysomethin0 is !ut to0ether) an# Pro!erty

State an# ariales o a System

*uation o State

as Laws

-inetic theory o ases

3eal ases

!


3/101

States o matter

Matter " #e$nition:

/00re0ation o atoms4ions4molecules which come withinthe sco!e o human e5!erience i%e% any sustance thathas mass an# occu!ies s!ace%

States of Matter:

$atter e5ists in one o the ollowin0 si5 states #ue to theener0y o its !articles& Gaseous, Liquid, Solid, Plasma,Bose-Einstein an# Filament. "he states o matter are also

6nown as !hases o matter or states o a00re0ation%

"he #i'ision o matter into states is not always sim!le%ow, or e5am!le, shoul# chocolate s!rea# e consi#ere#%Some scientists elei'e that the so calle# colloi#s shoul#

e consi#ere#%

%


4/101

/ssi0nment&

1) 7hat is Physical Chemistry8

2) 7hat are the classifcations in science8

9) :sin0 a #ia0ram illustrate the structure oscience

) 5!lain the ollowin0 terms&

Laws y!otheses "heories $o#els


5/101

+our states o matter

Base# u!on !article arran0ement

Base# u!on ener0y o !articles

Base# u!on #istance etween!articles

5

$atter is ma#e u! o !articles which are in

continual ran#om motion


6/101

State #eterminant Structureas

(sim!lest

state o

matter)

• -inetic ener0y is more

im!ortant than !otential

ener0y%

•


7/101

States o matter Soli#s

•Particles o soli#s areti0htly !ac6e#, 'iratin0

aout a f5e# !osition

•Soli#s ha'e a #efnite

sha!e an# a #efnite'olumeeat

'


8/101

States o matter Li*ui#

Particles o li*ui#s areti0htly !ac6e#, ut arear enou0h a!art to

sli#e o'er one another%

Li*ui#s ha'e an

in#efnite sha!e an# a#efnite 'olume%

eat

(


9/101

States o matter as

Particles o 0ases are'ery ar a!art an#mo'e reely

ases ha'e anin#efnite sha!e an#

an in#efnite 'olume

eat

)


10/101

Phase chan0es

#escri*tion ofPhase

Chan+e

Term forPhase

Chan+e

Heat Mo,ement#urin+

Phase Chan+e

Solid toli-uid

Meltin+Heat +oes intothe solid as it

melts./i-uid tosolid

0reein+Heat lea,es theli-uid as itfreees.

12


11/101

Phase chan0es

Descri!tiono PhaseChan0e

"erm orPhase

Chan0e

eat $o'ementDurin0

Phase Chan0e

Li*ui# to0as

a!ori?ation(oilin0 an#e'a!oration)

eat 0oes into theli*ui# as it'a!ori?es%

as to

li*ui# Con#ensation

eat lea'es the 0as

as it con#enses%

Soli# to0as

Sulimationeat 0oes into thesoli# as it

sulimates%

11


12/101

States o matter Plasma

/ !lasma is anioni?e# 0as%

/ !lasma is a 'ery

0oo# con#uctor oelectricity an# isa.ecte# y ma0neticfel#s%

Plasmas, li6e 0ases,ha'e an in#efnitesha!e an# anin#efnite 'olume%

Plasma

1!


13/101

States o matter

S@L


14/101

Pro!erty

/ !ro!erty is an essential or #istincti'e attriute (*uality) o somethin0; a *ualityor characteristics that somethin0 has

/ !ro!erty cannot e a unction o the!ast history (!re'ious con#itions un#erwhich it has e5iste#) o a system; it#e!en#s only on the con#itions at thetime o consi#eration

1&


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State unction

State 0unction& /ny system !ro!erty (measurale!hysical characteristic o a system, in#e!en#ent o how)#etermine# e5clusi'ely y the 'alues o the initial an#fnal states% 5am!les are :, , /, ", P, etc

Path 0unction& 3elate to the !re!aration o the state%5am!les, ener0y transere# as heat an# work that is#one in !re!arin0 a state

"hermo#ynamic lea#s to the #efnition o a##itional!ro!erties that can also e use# to #escrie the states oa system, an# are themsel'es state 'ariales% /, , %%

14


17/101

Basic conce!ts o thermo#ynamics

"he stu#y o the ow o heat or anyother orm o ener0y into or out o asystem as it un#er0oes a !hysical orchemical transormation%

"hermo#ynamics #eals with the inter

con'ersion o 'arious -in#s o ener0yan# chan0es in !hysical !ro!erties thatare in'ol'e#%

1'


18/101

"hree em!irical laws

"he stu#y o thermo#ynamics is ase#on three roa# 0eneralisations #eri'e#rom well estalishe# e5!erimental

results

"hese 0eneralisations are 6nown as the

+irst, Secon# an# "hir# law othermo#ynamics

1(


19/101

Sco!e o thermo#ynamics

$ost o the im!ortant laws o Physical Chemistrycan e #eri'e# rom the laws othermo#ynamics%


20/101

Limitations othermo#ynamics "hermo#ynamics is a!!licale to macrosco!ic

systems consistin0 o matter in ul6 an# not to

microsco!ic systems o in#i'i#ual atoms ormolecules%


21/101

"hermo#ynamic systems

/ !art o the !hysical uni'erse that isse!arate# rom the rest o the uni'ersey real or ima0inary oun#aries un#er

consi#eration or #iscussion%

!1


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23/101

omo0eneous systems

/ homo0eneous System is the system that isuniorm throu0hout

/ homo0eneous system is ma#e o one !hase

only

5am!les are & a !ure sin0le soli#, li*ui# or 0as,mi5tures o 0ases, an# true solution o a soli# in

a li*ui# / !hase is a homo0eneous, !hysically #istinct

an# mechanically se!arale !ortion o a system

!%


24/101

etero0eneous systems

/ hetero0eneous system is one whichconsists o two or more !hases%


25/101

"y!es o thermo#ynamic systems!5


26/101


27/101

Close# system

/ close# system is one which cannottranser matter ut can transer ener0yin the orm o heat, wor6 an# ra#iation to

an# rom its surroun#in0s%

"he oun#ary o a close# system is

seale# ut not insulate#%

!'


28/101

@!en system

"hereore, an o!en system is one whichcan transer oth ener0y an# matter toan# rom its surroun#in0s%

"he oun#ary o an o!en system is o!enan# uninsulate#%

!(


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30/101


31/101

5tensi'e !ro!erties

/ !ro!erty that #oes #e!en# on the*uantity o matter !resent in the system%

Some e5am!les o e5tensi'e !ro!ertiesare 'olume, numer o moles, enthal!y,entro!y, an# is ree ener0y%

%1


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33/101


34/101

State o a system

/ thermo#ynamic system is sai# to e in acertain state when all its !ro!erties are f5e#%

"he un#amental !ro!erties which #etermine

the state o a system are !ressure (P),tem!erature ("), 'olume (), mass an#

com!osition%

Since a chan0e in the ma0nitu#e o such!ro!erties alters the state o the system, theseare reerre# to as State 'ariales or Stateunctions or "hermo#ynamic !arameters%

%&


35/101

State o a system

/ chan0e o system rom the initial stateto the fnal state (2n# state) will eaccom!anie# y chan0e in the state

'ariales%


36/101

*uation o states

"he eha'iour o a 0aseous system can e #escrie#an# !re#icte# mathematically as

P f (",, n) (1)

"he !ressure P, is the #e!en#ent 'ariale an# thereare three in#e!en#ent 'ariales, ", an# n% "heletter f stan#s or the unctional relationshi!%

*n (1) !henomeno0ically summari?es em!iricaloser'ation calle# laws or rules i%e% reect someas!ect o the eha'iour o nature an# must thereoree correct (within limits o e5!erimental error)%

%4


37/101

*uation o states%'

"he e*uation o state or one mole o a!ure 0as is&

P 3"

where 3 is 0as constant%


38/101

De!en#ent an# in#e!en#ent 'ariales

%(

"he 'ariales (such as P an# ") whichmust e necessarily s!ecife# to #efnethe state o a system, are calle#


39/101

*uilirium states

%)

/ system in which the state 'ariales ha'econstant 'alues throu0hout the system issai# to e in a state o thermo#ynamice*uilirium%

If the frictionless piston is stationar, the state of the!as can "e speci#ed " !i$in! the $alues of pressure

and $olume.


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41/101

Criteria or e*uilirium&1

"he tem!erature o the system must euniorm an# must e the same as that othe surroun#in0s (thermal e*uilirium)

"he mechanical !ro!erties must e uniormthrou0hout the system (mechanicale*uilirium)

"he chemical com!osition o the systemmust e uniorm with no net chemical

chan0e (chemical e*uilirium)


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"hermo#ynamic !rocesses&!

7hen a thermo#ynamic system chan0esrom one state to another, the o!erationis calle# a Process%

/ !rocess in'ol'es chan0e in con#itions(tem!erature, !ressure an# 'olume)%


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44/101

/#iaatic !rocesses&&

"hose !rocesses in which no heat owsinto or out o the system, are calle#a#iaatic !rocesses%

/#iaatic con#itions can e a!!roache#y carryin0 the !rocess in an insulate#

container such as Fthermos ottle% i0h'acuum an# hi0hly !olishe# suraceshel! to achie'e thermal insulation%

+or an a#iaatic !rocess #* E


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46/101


47/101

Basic thermo#ynamic !rocesses&'


48/101

Cyclic !rocess&(

7hen a system in a 0i'en state 0oesthrou0h a numer o #i.erent !rocessesan# fnally returns to its initial state, the

o'erall !rocess is calle# a cycle or cyclic!rocess%

+or a cyclic !rocess # E, # E%


49/101

Cyclic !rocess&)


50/101

3e'ersile an# irre'ersile !rocesses

52

/ thermo#ynamic re'erse !rocess is one thatta6es !lace infnitesimally slowly an# its#irection at any !oint can e re'erse# y aninfnitesimal chan0e in the state o thesystem%

/ re'ersile !rocess !rocee#s rom the initialstate to the fnal state throu0h an infniteseries o infnitesimally small sta0es%

/t the initial, fnal an# all interme#iatesta0es, the system is in e*uilirium state%


51/101


51

7hen a !rocess 0oes rom the initial tothe fnal state in a sin0le ste! an#cannot e carrie# in the re'erse or#er, it

is sai# to e an irre'ersile !rocess%


52/101


5!

(a) 3e'ersile e5!ansion occurs y #ecreasin0 the!ressure on the !iston y infnitesimal amounts

()


53/101

3e'ersile an#


54/101

=ature o heat an# wor65&

/"& is a transer o ener0y as a resulto a tem!erature #i.erence etween thesystem an# the surroun#in0s


55/101

7or655

7or6 is a transer o ener0y that can euse# to chan0e the hei0ht o a wei0htsomewhere in the surroun#in0

@nly two ways in which the ener0y o aclose# system can e chan0e#& ytranserrin0 ener0y as wor6 or heat

7e shall reer the term Fwor6 ormechanical wor6 which is #efne# as orceG #istance


56/101

:nits o heat54

S< unit o heat is Houle ( I)

"he unit o heat, which was use# or manyyears, is calorie (cal)

/ calorie is #efne# as the *uantity o heatre*uire# to raise the tem!erature o 1 0ramo water y 1J C in the 'icinity o 1K JC

1 Houle E%29 calories

1 calorie %1M I

1 6cal %1M 6I


57/101

Si0n Con'ention o eat5'

"he symol o heat is *

*


58/101

Si0n con'ention or heat ow in a system

5(


59/101

Si0n Con'ention o 7or65)

"he symol o wor6 is w

w

Summary o Si0n


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Summary o Si0nCon'entions

42

eat ows into thesystem, * is N'e

eat ows out o thesystem, * is >'e

7or6 is #one on thesystem, w is N'e

7or6 is #one y thesystem, w is %$e


61/101

Pressure>olume 7or641

$echanical wor6 is #efne# as orcemulti!lie# y the #istance throu0h whichthe orce acts


62/101

Pressure>olume 7or64!

Consi#er a 0as containe# in a cylin#er ftte#with a rictionless !iston% "he !ressure (orce!er unit area) o the 0as, P, e5erts a orce onthe !iston% "his can e alance# y a!!lyin0

an e*ual ut o!!osite !ressure rom outsi#eon the !iston (Pe5t)%

3ememer that it is the e5ternal !ressure(Pe5t) an# not the internal !ressure o the 0as

itsel which is use# in e'aluatin0 wor6% "his istrue whether it e e5!ansion or contraction%

Pressure>olume 7or6


63/101

Pressure olume 7or6(5!ansion)

7or6 orce G #istance

w = f × l 16

Since pressure is force per area,f = P

ext × A !6

&here ' is the cross-sectionalarea of the piston,

+rom (1) an# (2),

w = Pext

× A x l

w = - Pext

×

78

4%

Since the system (0as) is #oin0 wor6 on the

surroun#in0s (!iston), it ears a >'e si0n%


64/101

Pressure>olume 7or6 (Com!ression)

Similarly, wor6 #one in com!ression o a 0as can

also e calculate#%


65/101

Class e5ercise45

Calculate the !ressure'olume wor6#one when a system containin0 a 0ase5!an#s rom 1%E litre to 2%E litresa0ainst a constant e5ternal !ressure o1E atmos!heres%


66/101


67/101


68/101


69/101


70/101


71/101


72/101


73/101

$a5imum wor6 #one in re'ersile e5!ansion

'%

(a) "he re'ersile wor6 o e5!ansion; () "heirre'ersile wor6 #one y the 0as when the e5ternal!ressure is at once #ro!!e# to the fnal 'alue %

$a5imum wor6 #one in re'ersile


74/101

$a5imum wor6 #one in re'ersilee5!ansion

'&

7or6 #one is much less in theirre'ersile e5!ansion than in there'ersile e5!ansion%

"hus mechanical wor6 is not a stateunction as it #e!en#s on the !ath ywhich the !rocess is !erorme# ratherthan on the initial an# fnal states%


75/101

$a5imum wor6 #one in re'ersilee5!ansion

'5

7or6 #one in the re'ersile e5!ansion o a 0as is thema5imum wor6 that can e #one y a system (0as

"his is ecause&

wor6 always #e!en#s on Pe5t; the lar0er the Pe5t the more

wor6 is #one y the 0as% But the Pe5t on the 0as cannot e more than the !ressure

o the 0as, P0as or a com!ression will ta6e !lace% "hus the

lar0est 'alue Pe5t can ha'e without a com!ression ta6in0

!lace is e*ual to P0as% But an e5!ansion that occurs un#er

these con#itions is the re'ersile e5!ansion% "hus, ma5imum wor6 is #one in the re'ersile e5!ansion

o a 0as%


76/101


77/101

Symol re!resentation o internal ener0y an# si0n con'entions

''

"he internal ener0y o a system is re!resente#y the symol (Some oo6s use the symol :)%


78/101

Sy o e! ese a o o e a e e 0yan# si0n con'entions

'(

in

O is N'e i is 0reater than in an# >'e

i is less than in%

/ system may transer ener0y to or rom

the surroun#in0s as heat or as wor6, or

: it i t l


79/101

:nits o internal ener0y

')

"he S< unit or internal ener0y o asystem is the Houle (I)%

/nother unit o ener0y which is not an S<unit is the calorie,

1 cal %1M I%

+i t l th # i


80/101

+irst law o thermo#ynamics

(2


81/101


7hen a system is chan0e#rom state / to state B, itun#er0oes a chan0e in theinternal ener0y rom / to B%

"hus,

O B > /

"his ener0y chan0e is rou0htaout y the e'olution orasor!tion o heat an#4or ywor6 ein0 #one y thesystem%

(1



82/101

+irst law o thermo#ynamics(!

Because the total ener0y o the system mustremain constant, we can write the +irst Law as&

O * > wwhere * the amount o heat su!!lie# to the system

w wor6 #one y the system

"hus +irst Law may also e state# as& the netener0y chan0e o a close# system is e*ual tothe heat transerre# to the system minus thewor6 #one y the system%

@ther #efnitions o frst law o thermo#ynamics


83/101

@ther #efnitions o frst law o thermo#ynamics

(%

1) 7hene'er ener0y o a !articular ty!e#isa!!ears e*ui'alent amount o anotherty!e must e !ro#uce#%

2) "otal ener0y o a system an# surroun#in0sremains constant (or conser'e#)

9)


84/101

Some s!ecial orms o frst law o thermo#ynamics

(&

$athematical statement o the +irst lawo "hermo#ynamics is

O * > w

Case 1 & +or a cyclic !rocess in'ol'in0

isothermal e5!ansion o an i#eal 0as

O E * w

Some s!ecial orms o frst law o


85/101

!thermo#ynamics

(5

Case 2 & +or an isochoric !rocess (no chan0ein 'olume) there is no wor6 o e5!ansion i%e%w E% ence O *'

Case 9 & +or an a#iaatic !rocess there is nochan0e in heat 0aine# or lost i%e% * E%ence

O > w i%e%, the #ecrease in internal ener0y is e5actly

e*ual to the wor6 #one on the system ysurroun#in0s%

Some s!ecial orms o frst law o


86/101

!thermo#ynamics

(4

Case & +or an isoaric !rocess there isno chan0e in !ressure, i%e% P remainsconstant%

ence

O * > w

O * > PO

nthal!y o a system


87/101

nthal!y o a system

('


88/101

:nits an# si0n con'entions o enthal!y


89/101

:nits an# si0n con'entions o enthal!y

()

O 2 > 1

O is !ositi'e i 2 Q 1 an# the !rocess or

reaction will e en#othermic%

O is ne0ati'e i 1 Q 2 an# the reaction will

e e5othermic%

22(0) N @2(0) 2@(l) N RM%92 6cal

"he *uantity o heat RM%92 6cal on the ri0hthan# re!resents > O o the reaction%

3elation etween O an# O


90/101

3elation etween O an# O)2

O O N PO

O O N On3"

+or the reaction ,

2+2(0) 2(0) N +2(0)

O > 1%2 6cal4mole at 2KJ C

Calculate O or the reaction%

$olar heat ca!acities


91/101


)1

eat ca!acity o a system is the heatasore# y unit mass in raisin0 thetem!erature y one #e0ree (- or J C) at as!ecife# tem!erature%

7hen mass consi#ere# is 1 mole, we can

write

where C is #enote# as $olar heat ca!acity%



92/101

$olar heat ca!acities)!

"he molar heat ca!acity o a system is#efne# as the amount o heat re*uire# toraise the tem!erature o one mole o thesustance (system) y 1 -%

"hus the molar heat ca!acity may e#efne# as the ratio o the amount o heatasore# to the rise in tem!erature%

:nits o heat ca!acity


93/101

:nits o heat ca!acity

)%

"he S< unit is Houles !er #e0ree !er mole

(I - >1mol>1)%

eat is not a state unction, neither is heatca!acity%


94/101

$olar heat ca!acity at constant 'olume (C')

)&

heat ca!acity at constant 'olume is#efne# as the rate o chan0e o internalener0y with tem!erature at constant'olume%

#* # N P#

Di'i#in0 oth si#es y #", we ha'e

/t constant 'olume # E, we 0et

dT

PdVdE

dT

dq +=

V

vdT

dEC

=

$olar heat ca!acity at constant !ressure, Cp


95/101

$olar heat ca!acity at constant !ressure, C p

)5

But, N P

Di.erentiatin0 w%r%t% ",

Com!arin0 (i) an# (ii)

.....(i)dT

PdV

dT

dEC +=

....(ii)dT

dVP

dT

dE

dT

dH

p p p

+

=

P

pdT

dHC

=

3elation etween C! an# C'


96/101

3elation etween C! an# C'

)4

/t a constant !ressure !art o heat asore# y thesystem is use# u! in increasin0 the internal ener0yo the system an# the other or #oin0 wor6 y thesystem%

7hile at constant 'olume the whole o heatasore# is utilise# in increasin0 the tem!erature othe system as there is no wor6 #one y the system%

"hus increase in tem!erature o the system woul#e lesser at constant !ressure than at constant'olume% "hus C! is 0reater than C'%

3elation etween C an# C


97/101

3elation etween C! an# C')'

"hus, C! is 0reater than C' y a 0asconstant whose 'alue is M%91 I - >1 mol>1%

+or n moles o an i#eal 0as,

O n 5 C! 5 ("2 "1)

R CC v p +=R CC v p =−

v

p

C

Cγ =

/#iaatic e5!ansion o an i#eal 0as


98/101

# aa c e !a s o o a #ea 0as

)(

/ !rocess carrie# in a 'essel whose walls are!erectly insulate# so that no heat can !assthrou0h them, is sai# to e a#iaatic%


99/101

/#iaatic e5!ansion o an i#eal 0as

))

+or a#iaatic e5!ansions,γ

2

1

1

2

V

V

P

P

=

γ

22

γ

11 VPVP =

k PV

γ

=

Com!arison etween isothermal an# a#iaatic e5!ansions


100/101

! !

122

"he #i.erence etween the two !rocesses is &in an isothermal !rocess, tem!erature o asystem remains constant while in an a#iaatic!rocess, tem!erature must chan0e%

P constant (Boyles law)

PS constant (/#iaatic

e5!ansion)

7or6 #one in a#iaatic re'ersile e5!ansion


101/101

!

121

7ma5 P(2 > 1)

7hen "2 Q "1, wma5 is ne0ati'e ecause 1 > is

ne0ati'e% "his means that wor6 is #one on the0as%

7hen "2 T "1, wma5 is !ositi'e which means

that wor6 is #one y the 0as%

γ1

)TT(R nW 12mx −

−=

notes on states of matter

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