1
Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
BE SEMESTER-VI EXAMINATION SUMMER 2017
Subject Code: 2163508 Date: 03/05/2017
Subject Name: Basics of Thermodynamics Kinetics
Time: 10:30 AM to 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1
Short Questions
14
1
At a inversion temperature, the joule-thomson coefficient is
01
Zero
positive
negative
infinite
2
Pure component molar volume is equal to partial molar volume in a binary mixture
01
always false
always true
true only for a mixture of ideal gases
cannot say
3
A larger positive value of ΔG0 corresponds to which of these
01
small positive K
large positive K
small negative K
Large negative K
4
The partial molar volume of a species in a liquid mixture becomes nearly equal to its pure component molar volume when the mole fraction(xi) of the species in the mixture
01
xi → 0
xi → 1
xi → infinity
cannot be predicted
5
Chemical potential
01
is an intensive property
is a force which drives the chemical system to equilibrium
of a substance is equal to its partial molar properties
All of these
6
Activity coefficient is measure of
01
2
Departure of a liquid from the ideal solution behavior
Departure of gas phase from ideal law
Tendency of a gas to achieve behaviour
None of these
7
During phase change which of the following state variable is continuous and remains unchanged at the transition point
01
Specific enthalpy
Specific entropy
Specific Gibbs free energy
Molar volume
8
The activity coefficient of benzene in benzene and toluene mixture can be assume to be equal to
01
Vapour pressure of benzene
Critical temperature of benzene
Mole fraction of benzene in the mixture
unity
9
For an ideal solution, which of the following equation(s) is not true
01
partial molar enthalpy of a species is equal to its pure molar enthalpy
partial molar entropy of a species is equal to its pure molar entropy
chemical potential of a species is equal to its pure molar gibbs free energy
None of the above
10
The molar extend of reaction is
01
Always greater than unity
Always less than unity
Can be greater than, equal to, or less than unity, depending on the reaction stochiometry
None of these
11
For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant
01
Is independent of pressure
Increases with pressure
Decreases with pressure
Increase/decreases with pressure depending on the stochiometry coefficient of the reaction
12
For a reversible exothermic gas phase reaction, A B ↔ the equilibrium conversion will increase with
01
3
Increase in pressure
and increase in
temperature
Decrease in pressure and
increase in temperature
Increase in pressure
and decrease in
temperature
Decrease in pressure and
decrease in temperature
13 With dilute aqueous solution of two salts are mixed, the process is
associated with
01
Decrease in
temperature
Increase in temperature
No change in
temperature
Change in temperature which is
a function of composition
14 The Maxwell relation derived from the differential expression for the
Helmholtz free energy is
01

s V S
P
V
T

















T P T
V
P
S

















s P S
V
P
T

















T V T
P
V
S
















Q.2 Define fugacity fugacity coefficient activity 03
Show that for ideal gas Cp-Cv R 04
Show that fugacity of a gas obeying the van der waals equation of state is
given by
07
OR
The equation of state of a certain substance is given by the expression
3
T
C
P
RT
V and the specific heat is given by the relation Cp A BT
where B and C are constant. Derive expressions for change in
internal energy, enthalpy and entropy for An isothermal process
An isobaric process
07
Q.3 Define Henry law Raoult' law Henry' law 03
Write short note on effect of temperature on chemical potential 04
The volume of an aqueous solution of NaCl at 298 K was measured for
a series of molalities(moles of solute per kg of solvent) and it was found
that the volume varies with molality according to the following
expression.
V a b c m1.5+ d m2 where m is the volatility and a 1.003 x 10-
3 b 0.1662 x 10-4 c 0.177 x d 0.12 x and V is in m3.
Calculate the partial molar volumes of the components at m 0.1
mol/kg.
07
OR
Q.3 Write Gibbs-Duhem equations in terms of fugacity activity
activity coefficient
03
Write short note on effect of pressure on activity coefficient 04
Prove that if Henry's law is obeyed by component 1 in a binary system
over certain concentration range Lewis-Randall rule( Raoult's law)
will be obeyed by component 2 over the same concentration range.
07
4
Q.4

Write down assumptions of Raolut's Law.
03

An equimolar solution of benzene and toluene is totally evaporated at a constant temperature of 363 K. At this temperature, the vapour pressures of benzene and toluene are 135.4 and 54 kPa respectively. What are the pressure at the beginning and at the end of the vapourization.
04

Derive van't Hoff equation
07
OR
Q.4

Draw and diagram for binary ideal solution.
03

Write a short note on determination of partial molar properties by graphical menthod.
04

A compound M polymeries in the gas phase at low pressure to Mn where n 1. show that the mole fraction of the polymer at equilibrium increases with increase in pressure at constant temperature the mole fraction of the polymer in the equilibrium mixture at 300 K is 0.15 at 1 bar and 0.367 at 2 bar. Find the value of n.
07
Q.5

Differentiate Elementary and non-Elementary reactions
03

Compare Integral method of analysis with differential method of analysis
04

The rate of bimolecular reaction at 500 K is 10 times the rate at 400 K. Calculate the activation energy of reaction by Arrhenius law and collision theory
07
OR
Q.5

Differentiate between Homogeneous reaction and Heterogeneous reaction
03

Discuss various forms of rate equation. Also explain variables affecting rate of reaction
04

On doubling the concentration of the reactants, the rate of reaction increase four times. Find the order of reaction
07