I IIIIII IIIIIIIIIIIIIIIIIIIIIIII IIII
.
..J
IV Semester
B']Sc:.Ed./M.Sc.Ed. , (Scheme:
Examination, R.I.E.)
April/May
Chemistry l'ht!rmodynamics, Equilibrium
Chemistry:
2012
and Solutions
Time: 3 Hours
Max. Marks
Instruction:
An~:w,9r all questions
and yoi1r answer
should
be brief
60
and
spE!cific. 1) a) Derive
express~ons
for W I l:1E, l:1H I q and W for In' ~oles
of an ideal gas
.
4
4
i) Determine t~e e~thalPY changes of slow react\9ns. ii) Calculate theJent~aJpy of formation of compounds
4
OR 2) a) Define
mOJar,hefrt (:apacity
at constant
(Cp) for a gas. S~OW that Cp -Cv
volume
(C" and at constant pressure
= R.
4
b)
Ji) Calcutate I~' ~orthe ;adi~p~tiq, r~ver~jbJe expansipn of 2 moles of an ideal gas at 273.2 K and 20 at~i,tQafinalpre~s~re c)
ExplaintheJerm
,,; ,
'heat
ofcombustionr.,H,Ow
substance can cIb~I determined
heat
usin g abomb'calorin1eter.
of2atm of
4
combustion,
of '
an :
:organic ii
"-
4
,. P. T.O.
22570
.2-
II. 3) a) Describe ifhe Carnot reversible cycle for establishing convertibility
the maximum
4
of heat into work.
b) The equilibrium
constant
Kp for a reaction
A + B --C
+ D is 10-12 at
.327°C amj 10-7 at 427°C. Calculate the enthalpy of the reaction. (R = 8.31,~ JK-1 mol-1).
4
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4
4
i) All spqnta~eous
processes I~ad~o,an increase in entropy of the universe.
ii) Enthalpy r~mains constant when a real gas passes thr.$Jugh a porous plug in an ~diabatic expansion. c)
Defrne"Chemical I
potential".
How
4 does
chemical
potential
with ~
temperatl Ire Jnd pressure ? III
vary
5), a) BasedlonIL~chateiier's
.N2(g) + '3t- 2(g)~
!
principl~,
4
workouttheconditions reaction~
2NH3(g) !!!H = -92.38
whjchwould favour : / "
KJ.11 r" ;;
;
N2(g) + O2( ::~ Q) ,;" I
2NO(g) !!!H = 180.75 c
,
Ccb) The SOIU~iiljty:prbd~tt!oi the solu~jiity of Mg(OH);
:
KJ.
c"
4
'
Mg(bH)2'~f2giJC in graM~lperlitr~.;
., i~'1'!4f~
16]11 (moldm~)3. ;i I
Calculate
4 'C) Stat~'th,~~wOf change
chemical
equilibrium;
~~d equilibriumcop~tant
OR
Derive the relation
betwee~, free energy
4
! .
22570
-3-
"' ~6)
a)
i) List out any ilourcharacteristics
of chemical equilibrium,
ii) How can the law of mass action be explained based on molecular collision theory ?
4
b} A buffer solution c:ontains 0.015 mole of NH4OH and 0.025 mole of NH4CI, Calculate pH vcllule of the solution. Given: at 25°C.
I i) CH3COONa
Kb(NH4OH} = 1.80 x 10-5 4
is basic while NH4CI is acidic in nature.
on resists changes in pH
ii) Buffer solu1l
4
~ IV.
7) a) State Gibb's pr ase rule. Discuss Its application b)
Describe
how II 1~:~i~~~r~~~haSe
equil:b;iUm
to water system. is used in the preparation
4 of
dry ice a~dfreE
4
c) Determine the ilumber of component~, freedom for thd "following systems : , I
ii)
CO2(S)~~
number of phases and degrees of
Cb~(g) I
iii)
N2O 4(g)=--
iv)
NH4CI(g):::;=,
~.:. 2No2(g}
4
OR
I
8) a) Derive Gibbjs p
4
b) Draw phaseldic form. i i) a eutectic rr,lxture
t
,
, ii)
a stable
I'
con
pound
with
. .
arcongruent "
c) Explain how Clapeyron-Clausius
melting
point.
4
equation can be used for
i) Determlna~i9n of enthalpy of vaporisation of a liquid. ii) Studying t~13reffectof pressure on boiling point and freezing point of a liquid.
I }
4
22570
-4.
V. 9) a) State Her~/s
law of gas solubilities
~
mention its limitations.
At a pressure of 760 mm, a mixture of C6HsNO2 and water boils at 99°C. The vapour pref,SUre of water at this temperature of water ;3.nrdnitrobenzene
is 733 mm. Find the proportion
in the distillate obtained by steam distillation
commer(~ial C6HSNO2"
of
I
b) Write shprt note on the application
of distribution
i) Solv nt extraction and
law in
r
.\'
1
ii) Park I'S process.
I i c) How is t le molecular mass of a solute determined from elevation of boiling
.
point in 1e laboratory ? OR 10)
a)
i)1 Draw and explain ' ~~ watei Sy&tern ,
the temperatur$ .i' ",-' Ic
,
,
'c
.,c
, ,"C
,!"
" !
I
composition
of Tri ethylamine
"\
c, "
"
ii) EXPI~linhlow CST of phenOI-w~t,tsySIetn solutfo~.1 j (
diagram
varies withthe,~ddjtion
j ("j
of KCI
~- "
b) With the'aid pf boiling point -% COmPosition curves for miscible binary liquid mixtures, di~cuss the separation
of components
by fractional
distillation.
c) State ,Nern~)tpistribution law the following data were obtained for the distribution of an !orglani~ solute between water (C1) and chloroform (C2) at 25°C.
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