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7/24/2019 Lecture 1 - Phase Equilibrium
1/73
8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( O*+e,ti$e :At te en o/ tis lesson st0ents so0l *e #*le to:
#2 3e/ine p#se #n ,omponent.
*2 3e/ine t%iple point #n ,%iti,#l point.
,2 S4et, #n e5pl#in te p#se i#g%#m o/ HO
#n CO.
E5pl#in te #nom#lo0s *e#$io0% o/ HO.
2 3es,%i*e te ,#nges in p#se !it %espe,t toi. tempe%#t0%e #t ,onst#nt p%ess0%e2
ii. p%ess0%e #t ,onst#nt tempe%#t0%e2.
P#se 6 Component
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( 3e/initions
PHASE :The phases of a system are parts of it which are
separated by a distinct boundary, such as solid, liquid
and gas.Homogenous part of a system which is chemically and
physically uniform.
E5#mple
Rel#tionsip
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
3e/inition
E5e%,ise
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
A two-phase system is one containing either
- a gas and a solid
- a gas and a liquid
- a solid and a liquid
- a solid and a solid
- two immiscible liquids
A three-phase system is one containing either
- a solid, a liquid, and a gas
- two immiscible liquids and a gas
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
3e/initions
CO(PO&E&T :CO(PO&E&T :
A component is a chemically independent constituent of a system. The
number of components in a system is the minimum number of independentspecies necessary to define the composition of all the phases present in the
system.
The number of components in a phase system is the minimum number of
chemical entities needed to define all the phase of the system
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( E5#mple :
E5#mple
Rel#tionsip
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
3e/inition
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( Rel#tionsip *et!een System7 P#se 6 Component
System P C 3es,%iption
Mixtureof gases
!ependtypes of
gases
"ases are well mixed.#e cannot see
the boundary betweenthe gases.
Two liquids!o not mix$oil-water%
& & #e can see the boundarybetween the two liquid,
Two liquidswell mixed
$alcohol-water%
& #e cannot seethe boundary of
the solution.
E5#mple
Rel#tionsip
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
3e/inition
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( 3e/initions
PHASE 3IA'RA( :A graphical plot of pressure 's temperature that shows
the conditions at which a substance exists as a solid,
liquid or gas in a one component system.
(hows the conditions under which equilibrium exists
between the different states of matter.
A typical phase diagram has three regions ) solid, liquidand gas. *ach of these region is separated by their
boundary lines $i% solid+gas $ii% solid liquid and $iii% liquid
gas.
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( 3e/initions
CRITICAL POI&T :At this point and abo'e, it is not possible to liquefy a
gas howe'er great the pressure is. ndeed the term
'apour should only be used below the critical point, asit implies that it is possible to form a liquid.
TRIPLE POI&T :TRIPLE POI&T :
Triple point is an unique point at which the three linesrepresenting the solid+liquid, liquid+'apour and
solid+'apour equilibriums. t represents the conditions at
which all the three phases can co-exist in a stable
manner and each is at equilibrium with the other two.
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( 3e/initions
CRITICAL TE(PERATURE :
The highest temperature at which a gas can
be liquefied.
CRITICAL PRESSURE :
The pressure required to liquefy a gas at the
critical temperature.
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( P#se 3i#g%#m o/ HO
C%iti,#l Point
T%iple Point
1oC
1 #tm
oC Tempe%#t0%e oC2
P%e
ss0%e1#tm2
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
C0%$e 3es,%iption
E5pl#n#tion
Anom#lo0s Be#$io%
P#se 6 Component
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
C0%$es in P#se 3i#g%#m o/ HO
C%iti,#l Point
T%iple Point
1oC
1 #tm
oC
Tempe%#t0%e oC2
P%ess0%e1#tm2
T-C: Rep%esents te $#%i#tion o/T-C: Rep%esents te $#%i#tion o/ *oiling*oilingtempe%#t0%e !it pess0%etempe%#t0%e !it pess0%e
T
A
B C
T-B: Rep%esents te $#%i#tion o/T-B: Rep%esents te $#%i#tion o/ meltingmeltingtempe%#t0%e !it pess0%etempe%#t0%e !it pess0%e
T-A: Rep%esents te $#%i#tion o/T-A: Rep%esents te $#%i#tion o/ s0*lim#tions0*lim#tiontempe%#t0%e !ittempe%#t0%e !it
pess0%epess0%e
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
C0%$e 3es,%iption
E5pl#n#tion
Anom#lo0s Be#$io%
P#se 6 Component
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( E5pl#n#tionAt lo! tempe%#t0%es #n #tmospe%i, p%ess0%e7 teAt lo! tempe%#t0%es #n #tmospe%i, p%ess0%e7 test#*le p#se is test#*le p#se is te soli i,e2.soli i,e2.
At 1 #tm7 te tempe%#t0%e #t !i, i,e #n !#te% #%e #tAt 1 #tm7 te tempe%#t0%e #t !i, i,e #n !#te% #%e #t
e90ili*%i0m7 is ,#lle tee90ili*%i0m7 is ,#lle te melting pointmelting point C 7 ;".1< =2.C 7 ;".1< =2.
Te line sep#%#tes te soli #n li90i p#ses. As tisTe line sep#%#tes te soli #n li90i p#ses. As tisline is not $e%ti,#l7 te t%#nsition /%om soli to li90iline is not $e%ti,#l7 te t%#nsition /%om soli to li90i
t#4es pl#,e #t i//e%ent tempe%#t0%es 0ne% i//e%entt#4es pl#,e #t i//e%ent tempe%#t0%es 0ne% i//e%ent
p%ess0%es.p%ess0%es.
At tempe%#t0%es *et!een At tempe%#t0%es *et!een C #n 1C #n 1C 0ne% 1C 0ne% 1
#tmospe%i, p%ess0%e7 te st#*le p#se is li90i !#te%.#tmospe%i, p%ess0%e7 te st#*le p#se is li90i !#te%.
At 1At 1C7 te line %ep%esenting te e90ili*%i0m *et!eenC7 te line %ep%esenting te e90ili*%i0m *et!een
li90i #n g#s is %e#,e #n te tempe%#t0%e #t !i,li90i #n g#s is %e#,e #n te tempe%#t0%e #t !i,
*oiling t#4es pl#,e 0ne% #tmospe%i, p%ess0%e is te*oiling t#4es pl#,e 0ne% #tmospe%i, p%ess0%e is te
*oiling point.*oiling point.Te *oiling point $#%ies #s te p%ess0%eTe *oiling point $#%ies #s te p%ess0%e
'aries.'aries.
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
C0%$e 3es,%iption
E5pl#n#tion
Anom#lo0s Be#$io%
P#se 6 Component
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( Anom#lo0s Be#$io% o/ HOThe phase diagram for water is not typical, the meltingThe phase diagram for water is not typical, the melting
temperature line , T-/ ,temperature line , T-/ , slopes to te le/tslopes to te le/t i.e. the meltingi.e. the melting
temperature decreases with pressure.temperature decreases with pressure.
This is connected with the fact thatThis is connected with the fact that ice is less dense thanice is less dense thanwater, while most solids are denser than their liquids.water, while most solids are denser than their liquids.
TheThe melting ,0%$emelting ,0%$eoror /0sion ,0%$e/0sion ,0%$eof ice + water is 'eryof ice + water is 'ery
special. t has a negati'e slope due to the fact that)special. t has a negati'e slope due to the fact that)
when ice melts, the molar volume decreases. Icewhen ice melts, the molar volume decreases. Ice
actually melt at lower temperature, higher pressure.actually melt at lower temperature, higher pressure.
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
C0%$e 3es,%iption
E5pl#n#tion
Anom#lo0s Be#$io%
P#se 6 Component
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( P#se 3i#g%#m o/ CO
T%iple Point
C%iti,#l Point
Tempe%#t0%e oC2
P%e
ss0%e1#tm2
C0%$e 3es,%iption
E5pl#n#tion
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
T%iple Point
C%iti,#l oint
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
C0%$es in P#se 3i#g%#m o/ CO
P%e
ss0%e1#tm2
T
A
B C
Tempe%#t0%e oC2
T-C: Rep%esents te $#%i#tion o/T-C: Rep%esents te $#%i#tion o/ *oiling*oilingtempe%#t0%e !it p%ess0%etempe%#t0%e !it p%ess0%e
T-B: Rep%esents te $#%i#tion o/T-B: Rep%esents te $#%i#tion o/ meltingmeltingtempe%#t0%e !it pess0%etempe%#t0%e !it pess0%e
T-A: Rep%esents te $#%i#tion o/T-A: Rep%esents te $#%i#tion o/ s0*lim#tions0*lim#tiontempe%#t0%e !ittempe%#t0%e !it
p%ess0%ep%ess0%e
C0%$e 3es,%iption
E5pl#n#tion
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
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TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8.1 - SI&'LE8.1 - SI&'LE
CO(PO&E&T S)STE(CO(PO&E&T S)STE( E5pl#in#tionThe phase diagram of carbon dioxide is moreThe phase diagram of carbon dioxide is more typi,#ltypi,#l,,showing ashowing a rightward slopingrightward slopingmelting temperature line.melting temperature line.
T%iple pointT%iple pointfor carbon dioxide is -0123 $ &4.5 6 % and 0.&for carbon dioxide is -0123 $ &4.5 6 % and 0.&
atm $ 04 78a %. The triple point is abo'e atmosphericatm $ 04 78a %. The triple point is abo'e atmospheric
pressure, so that at atmospheric pressure carbon dioxidepressure, so that at atmospheric pressure carbon dioxidesublimes, so dry ice, which is solid carbon dioxide, changessublimes, so dry ice, which is solid carbon dioxide, changes
directly from solid to gas.directly from solid to gas.
At this pressure, the liquid phase is not stable, the solidAt this pressure, the liquid phase is not stable, the solid
simply sublimes. Thus solid carbon dioxide is calledsimply sublimes. Thus solid carbon dioxide is called %y i,e%y i,e,,
because it does not go through a liquid state in its phasebecause it does not go through a liquid state in its phasetransition at room pressure.transition at room pressure.
The critical temperature for carbon dioxide is 9.:3, andThe critical temperature for carbon dioxide is 9.:3, and
the critical pressure is 19 atm. Abo'e the critical temperature,the critical pressure is 19 atm. Abo'e the critical temperature,
the fluid is called super-critical fluid.the fluid is called super-critical fluid.
C0%$e 3es,%iption
E5pl#n#tion
T%iple Point 6 C%iti,#l Point
P#se 3i#g%#m HO
P#se 3i#g%#m CO
P#se 6 Component
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
. !etermine the stable phase of 3arbon !ioxide ata% ;.10 atm and -4; o3
b% 0.0; atm and -1; o3
&. #hat is the physical state of water under each of the following
conditionsO8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
O*+e,ti$e :
/2 3e/ine #@eot%opi, mi5t0%e.
3ete%mine te ,omposition o/ #@eot%opi, mi5t0%e
/%om # *oiling point-,omposition i#g%#m.
g2 E5pl#in te p%in,iples in$ol$e in simple #n/%#,tion#l istill#tions o/ # *in#%y mi5t0%e.
2 3ete%mine te istill#te #n %esi0e o/ #
istill#tion /%om te *oiling point-,omposition i#g%#m.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
1
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( (is,i*ility
(ISCIBLE:
Two liquids are considered >miscible> or
mixable if sha7ing them together results in a
single liquid phase , with no meniscus 'isible
between layers of liquids.
Miscible refers to the property of 'ariousliquids that allows them to be mixed together.
*xample ) Methanol ? #aterMethanol ? #ater
(is,i*ility
(is,i*le
P#%ti#lly (is,i*le
Immis,i*le
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Ie#l Sol0tion
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( (is,i*ility
PARTIALL)PARTIALL) (ISCIBLE::
#hen one liquid partially dissol'es in the
other, the result is two solutions appearingas two layers. These two liquids are
considered to be partially miscible
*xample ) Hexanol ? #aterHexanol ? #ater
(is,i*ility
(is,i*le
P#%ti#lly (is,i*le
Immis,i*le
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( (is,i*ility
I(I((ISCIBLE::
Two liquids are considered >immiscible> or
unmixable if sha7ing equal 'olumes of theliquids together results in a meniscus 'isible
between two layers of liquid, the 'olumes of
the liquid layers are the same as the 'olumes
of liquids orginally added to the mixture.
mmiscible refers to the property of 'arious
liquids that if they cannot be mixed together.
*xample ) @il ? #ater@il ? #ater
(is,i*ility
(is,i*le
P#%ti#lly (is,i*le
Immis,i*le
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Ie#l Sol0tion
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TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( P%ope%ties O/ #n ie#l Sol0tion
A solution containing a mixture of liquid A and liquid /
is ideal solution if ,
the three different intermolecular forces A-A, /-/and A-/, are of the same type and comparable in
strengthand expect the molecules to intermingle
randomly into a solution. there is no energy changein the formation of the
solution , HsolutionB ;.
the 'olume of the solution is the sum of the
'olumes of the two liquids A and /, CsolutionB ;
@beys the Daoults law.
8actualB 8 measured$calculated%
The measured 'apour pressureof the solution isthe same as that predicted by the Daoults Eaw.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
3i#g%#m
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
#po0% p%ess0%e 6 *oiling point i#g%#m
o/ #n ie#l Sol0tion(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
3i#g%#m
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( 3e/inition
R#o0ltDs l#!states that the 'apor pressure of each
component in an ideal solution is dependent on the
'apor pressure of the indi'idual component and the
mole fraction of the component present in the solution.
@nce the components ha'e reached equilibrium in the
solution, the total 'apor pressure of the solution is)
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
C#l,0l#tion
E5#mple Q0estion
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( C#l,0l#tion
The partial pressure of a sol'ent o'er a solution, PA, is gi'en
by the 'apour pressure of the pure sol'ent, 8oAtimes the mole
fraction of the sol'ent in the solution, FA)
PABFA8oA
n a solution containing only one solute, AF 1 G B, where
Bis the mole fraction of the solute. The abo'e equation can
be rewritten as G
PA F 1 G B2 PoA
PA
F Po
A
G B
PoA
Po G P F P F Po
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
C#l,0l#tion
E5#mple Q0estion
1"
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8.1 - Single Component System
TOPIC 8 : PHASE EQUIBLIBRIA
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( C#l,0l#tion
Sol0tions t#t ,ont#in mo%e t#n one $ol#tile ,omponents
n many solutions such as benene and carbon
tetrachloride, both solute and sol'ent ha'e appreciabletendencies to undergo e'aporation.
n this case, the 'apour will contain both solute and
sol'ent molecules, and the 'apour pressure of the
solution will be the sum of the partial pressures exertedby each component.
The partial pressure of any component abo'e such a
mixture is also gi'en by Daoults Eaw.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
C#l,0l#tion
E5#mple Q0estion
1"
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( C#l,0l#tion
Sol0tions t#t ,ont#in mo%e t#n one $ol#tile ,omponents
Thus, the partial pressure of component A , 8Ais gi'en by )
PA F APOAwhere )
8A B the 'apour pressure of pure A
FA B the mole fraction of A in the solution
(imilarly , the partial pressure of component / , 8/is )
PBF BPOB
where )
8/B the 'apour pressure of pure /
F/B the mole fraction of / in the solution
Iinally , the total 'apour pressure of a mixture of A and / is gi'en by
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
C#l,0l#tion
E5#mple Q0estion
1"
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( C#l,0l#tion
C#l,0l#ting te #po0% P%ess0%e o/ # Sol0tion o/
t!o $ol#tile ,omponents
E5#mple :
A mi5t0%e ,ont#ining
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
C#l,0l#ting te #po0% P%ess0%e o/ # Sol0tion o/
t!o ol#tile Components
Sol0tion : /y using Daoults Eaw,
Jo of moles ) component A, 33l5 B ;.9&0 mol 33l5component /, 3H3l9B ;.5K mol 3H3l9
Mole fractions )
CCl B ;.9&0 B ;.591
$;.9&0 L ;.5K%
CHCl B ;.5K B ;.049
$;.9&0 L ;.5K%
8artial pressure of each component abo'e the solution )
PCClF CClPCCl B $;.591%$91 torr% B 9K torr
PCHClF CHClPCHCl B $;.049%$0&4 torr% B &K4 torr
Total 'apour pressure )F B L
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
C#l,0l#tion
E5#mple Q0estion
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( &on-Ie#l sol0tion
Actually, 'ery few mixtures really obey
Daoults law. sually, the measured 'apour
pressure of the solution is either larger orsmaller than Daoults law.
f the 'apour pressure of the solution is larger
than Daoults Eaw, the solution will shows
positi$e e$i#tion
f the 'apour pressure of the solution
issmaller than Daoults Eaw, the solution will
shows neg#ti$e e$i#tion
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Positi$e 3e$i#tion
&eg#ti$e 3e$i#tion
O C S Q
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( &on-Ie#l sol0tion : Positi$e 3e$i#tion
Composition-$#po0% p%ess0%ecur'e for a solutions that
shows positi'e de'iations from Daoults law
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Positi$e 3e$i#tion
&eg#ti$e 3e$i#tion
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( &on-Ie#l sol0tion : Positi$e 3e$i#tion
Composition-$#po0% *oiling tempe%#t0%e i#g%#m /o% #
sol0tions t#t so!s positi$e e$i#tions /%om R#o0lt?s
l#!
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Positi$e 3e$i#tion
&eg#ti$e 3e$i#tion
TOPIC 8 PHASE EQUIBLIBRIA
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
&on-Ie#l sol0tion : Positi$e 3e$i#tion
#hen te #tt%#,ti$e /o%,es *et!een te sol0te #n
sol$ent mole,0les #%e !e#4e% t#n tose *et!een sol0te
mole,0lesor between sol'ent molecules, $A-A , /-/ N A-/%
neither the solute nor sol'ent particles are held as tightly in
the solution as they are in the pure substances.
The escaping tendency of each is therefore greater in the
solution than in the solute or sol'ent alone.
As a result, the partial pressures of both of them o'er the
solution are greater than that predicted by Daoults law.
Therefore, te sol0tion #s # l#%ge% $#po0% p%ess0%ethan
expected and exhibit a positi'e de'iation from Daoults law.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Positi$e 3e$i#tion
&eg#ti$e 3e$i#tion
TOPIC 8 PHASE EQUIBLIBRIA
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( &on-Ie#l sol0tion : &eg#ti$e 3e$i#tion
Composition-$#po0% p%ess0%ecur'e for a solution that
shows negati'e de'iations from Daoults law
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Positi$e 3e$i#tion
&eg#ti$e 3e$i#tion
TOPIC 8 PHASE EQUIBLIBRIA
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( &on-Ie#l sol0tion : &eg#ti$e 3e$i#tion
Composition-$#po0% *oiling tempe%#t0%e i#g%#m /o% #
sol0tion t#t so! neg#ti$e e$i#tions /%om R#o0lt?s l#!
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Positi$e 3e$i#tion
&eg#ti$e 3e$i#tion
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CO(PO&E&T S)STE(CO(PO&E&T S)STE( &on-Ie#l sol0tion : &eg#ti$e 3e$i#tion
The opposite effect is produced when the solute-sol'ent
attractions are larger than the solute-solute and sol'ent-
sol'ent attractions A-B M A-A 7 B-B2.
*ach substance is held more tightly in the presence of eachother than in their pure liquids.
As a result, their partial pressures o'er the solution are less
than Daoults law would predict and their solutions show
neg#ti$e e$i#tions.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Positi$e 3e$i#tion
&eg#ti$e 3e$i#tion
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( Ie#l Sol0tion &on-Ie#l Sol0tion
Positi$e e$i#tion &eg#ti$e e$i#tion
S0mm#%y o/ sol0tion p%ope%ties
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( A@eot%ope :
An aeotrope is a mixture with the s#me te
,omposition o/ # $#po0% #n li90iand has
,onst#nt *oiling pointand ,#nnot *e
sep#%#te *y istill#tion.
A solution that shows positi$e e$i#tionsfrom
Daoults law, exhibits a minim0m-*oiling
#@eot%opeand m#5im0m-$#po0% p%ess0%e
#@eot%ope.
A solution that shows neg#ti$e e$i#tions
from Daoults law, exhibits a m#5im0m-*oiling
#@eot%opeand minim0m-$#po0% p%ess0%e
#@eot%ope.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( 3istill#tion
A technique used for the separation of
components of a solution by boiling the
solution and then condensing its 'apour.
(imple distillation
Iractional distillation
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( Simple 3istill#tion
(imple distillation is a procedure by which two
liquids with different boiling points can be
separated .
(imple distillation is effecti'e only when
separating a 'olatile liquid from a non'olatile
substance or when separating two liquids that
differ in boiling point by 0; degrees or more.
(imple distillation is carried out without any
column pac7ing, n theory, simple distillation
in'ol'es as few as one theoretical plate .
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( Simple 3istill#tion App#%#t0s(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( N%#,tion#l 3istill#tion
Iractional distillation is a method to separatemixtures of liquids with boiling points that are
close to each other by repeated simple
distillation process.
n fractional distillation, the 'apors formedfrom the boiling mixture rise into thefractionating column where they condense on
the columnOs pac7ing.
As 'apors continue to rise through thecolumn, the liquid that has condensed will
re'aporie.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( N%#,tion#l 3istill#tion App#%#t0s(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
N%#,tion#l istill#tion o/ *in#%y mi5t0%e A 6 B2
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
N%#,tion#l istill#tion o/ *in#%y mi5t0%e A 6 B2
A fractionating column produces the effect of many
successi'e boiling and condensation cycles
automatically.The column sies ha'e a large surface area. The
liquid mixture boils and the 'apour rises up thecolumn.As the temperature drops, the 'apour condenses,
the liquid $richer in A% drops bac7 into the boiling flas7
and the 'apour $richer in /% mo'es up the column.
This happens many times as the 'apour rises up thetube.A long enough column will result in a 'apour of pure
/ at the top of the column and e'entually pure A left
in the boiling flas7.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE( Composition o/ #@eot%opi, mi5t0%e
Te%e #%e some sol0tions t#t e5i*it $e%y l#%ge
e$i#tions /%om ie#lity.
(olutions exhibit positi'e de'iationsfrom Daoults law
(olutions exhibit negati'e de'iations
from Daoults law
As # %es0lt7 tey ,#nnot *e tot#lly sep#%#te into
tei% ,omponents e$en *y /%#,tion#l istill#tion.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
100
78.5
100% !#te%100% et#nol
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
Sol0tions e5i*it positi$e e$i#tions
/%om R#o0lt?s l#!
These solutions ha'e a maximum in the 'apour pressure
cur'e and hence a minimum in the boiling point. !iagram
such a solution has minim0m-*oiling #@eot%ope.
Te *oiling point i#g%#m /o% !#te%-et#nol mi5t0%e
A@eot%opi, Composition
!#te%: .
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
N%#,tion#l 3istill#tion et#nolG!#te% mi5t0%e
*thanol-water mixtures $obtained by fermentation of
sugar for example%, are rich in water.
Iractional distillation is able to concentrate the alcohol
to, at best, aeotropic composition of approximately
K0P by 'olume of ethanol.
@nce this composition has been achie'ed, the liquid
and 'apour ha'e the same composition, and noadditional fractionation ta7es place.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
78.5
100
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
Sol0tions e5i*it neg#ti$e e$i#tions
/%om R#o0lt?s l#!
These solution ha'e a minimum in the 'apour pressure cur'e
and hence a maximum in the boiling point diagram. A solution
with such a maximum boiling point is called a m#5im0m-
*oiling point #@eot%ope.
Te *oiling point i#g%#m /o% nit%i, #,i-!#te% mi5t0%es
100% water 100% HNO3
Tem
pe%#t0%e
A@eot%opi, Composition$9.=P water and 4=.&P HJ@9%
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8. - T>O8. - T>O
CO(PO&E&T S)STE(CO(PO&E&T S)STE(
N%#,tion#l istil#tion nit%i, #,iG!#te% mi5t0%e
Iractional distillation is able to concentrate the nitric
acid. Irom the diagram, this aeotropic mixture can be
separating them into, at best, one pure component plus
a solution ha'ing the maximum boiling point $aeotropic
composition%.
Iractional distillation is able to concentrate the nitric
acid.
(is,i*ility
Ie#l Sol0tion
R#o0lt?s L#!
&on-ie#l Sol0tion
A@eot%ope
3istil#tion
Simple istill#tion
N%#,tion#l istill#tion
3istill#tion *in#%y mi5t0%e
A@eot%opi, mi5t0%e
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
8." - COLLI'ATIE8." - COLLI'ATIE
PROPERTIESPROPERTIES O*+e,ti$e :At te en o/ tis lesson st0ents so0l *e #*le to:
#2 3e/ine ,ollig#ti$e p%ope%ties.
*2 3es,%i*e te ,ollig#ti$e p%ope%ties o/ # sol0tion:
i. lo!e%ing o/ $#po0% p%ess0%e
ii. *oiling point ele$#tion
iii. /%ee@ing point ep%ession
i$. osmoti, p%ess0%e
,2 Pe%/o%m ,#l,0l#tions on ,ollig#ti$e p%ope%ties o/# non-ele,t%olyte sol0tion ,ont#ining non-$ol#tile
sol0tes.
Collig#ti$e p%ope%ties
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8. - T!o Component System 8." - Collig#ti$e P%ope%ties
Collig#ti$e p%ope%ties
8roperties of solutions which depend on the
number of molecules present and not on the
7ind of molecules.
Iour colligati'e properties are )
. Capour pressure lowering
&. Ireeing point depression9. /oiling point ele'ation
5. @smotic pressure
Collig#ti$e p%ope%ties
#po0% p%ess0%e lo!e%ing
N%ee@ing point ep%ession
Boiling point ele$#tion
Osmoti, p%ess0%e
8." - COLLI'ATIE8." - COLLI'ATIE
PROPERTIESPROPERTIES
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8.1 - Single Component System
Q
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
Te e//e,t o/ # non$ol#tile sol0te on te p#se
i#g%#m /o% !#te%.
#hen a solute is added to pure sol'ent, the mole fraction
decreases. Addition of a solute at constant T and 8 lowers the
sol'ent chemical potential.
Collig#ti$e p%ope%ties
#po0% p%ess0%e lo!e%ing
N%ee@ing point ep%ession
Boiling point ele$#tion
Osmoti, p%ess0%e
8." - COLLI'ATIE8." - COLLI'ATIE
PROPERTIESPROPERTIES
TOPIC 8 : PHASE EQUIBLIBRIA
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System
Q
8. - T!o Component System 8." - Collig#ti$e P%ope%ties
#po0% p%ess0%e lo!e%ing
The change in 'apor pressure where the solute is
less 'olatile than the sol'ent is regulated by
DaoultOs law, which states that the pressure is
equal to the mole fraction of the sol'ent times the'apor pressure of pure sol'ent) 8BFsol'entQ8:.
The change in the 'apor pressure occurs when a
solute is added to a sol'ent.
f a non'olatile solute $one that has no tendency
to escape from a solution% is dissol'ed in a liquid
sol'ent, the 'apour pressure of the sol'ent is
lowered.
Collig#ti$e p%ope%ties
#po0% p%ess0%e lo!e%ing
N%ee@ing point ep%ession
Boiling point ele$#tion
Osmoti, p%ess0%e
8." - COLLI'ATIE8." - COLLI'ATIE
PROPERTIESPROPERTIES
TOPIC 8 : PHASE EQUIBLIBRIA
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System 8. - T!o Component System 8." - Collig#ti$e P%ope%ties
#po0% p%ess0%e lo!e%ing
#hen a solute is added to the sol'ent, some of the solute
molecules occupy the space near the surface of the liquid, as
shown. #hen a solute is dissol'ed in a sol'ent, the number of
sol'ent molecules near the surface decreases, and the 'apor
pressure of the sol'ent decreases.
t decreases the rate at which the sol'ent molecules in the liquid
can escape into the gas phase. As a result, the 'apor pressure
of the sol'ent escaping from a solution should be smaller than
the 'apor pressure of the pure sol'ent.
P Po
Collig#ti$e p%ope%ties
#po0% p%ess0%e lo!e%ing
N%ee@ing point ep%ession
Boiling point ele$#tion
Osmoti, p%ess0%e
8." - COLLI'ATIE8." - COLLI'ATIE
PROPERTIESPROPERTIES
TOPIC 8 : PHASE EQUIBLIBRIA
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System 8. - T!o Component System 8." - Collig#ti$e P%ope%ties
C#l,0l#tion $#po0% p%ess0%e lo!e%ing
APBX=A
P-A
P
APBX-A
P=A
P
A)P
BX-(1=
AP
1=BX+AX
solventP
solventX=
solutionP
ABA PXP =
Collig#ti$e p%ope%ties
#po0% p%ess0%e lo!e%ing
N%ee@ing point ep%ession
Boiling point ele$#tion
Osmoti, p%ess0%e
8." - COLLI'ATIE8." - COLLI'ATIE
PROPERTIESPROPERTIES
TOPIC 8 : PHASE EQUIBLIBRIA
7/24/2019 Lecture 1 - Phase Equilibrium
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8.1 - Single Component System 8. - T!o Component System 8." - Collig#ti$e P%ope%ties
C#l,0l#tion $#po0% p%ess0%e lo!e%ing
The 'apour pressure of pure water at &4o3 is
&0.& torr. #hat is the 'apour pressure of a
solution which contains &;.; g glucose,
34H&@4in 1; g water
Recommended