GTU BE 5th Semester 150503 Chemical Engineering Thermodynamics-II Summer 2018 Question Paper

1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE – SEMESTER?V (OLD) – EXAMINATION ? SUMMER 2018
Subject Code:150503 Date:30/04/2018
Subject Name:Chemical Engineering Thermodynamics-II
Time:02:30 PM to 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define partial molar properties. Discuss various methods for evaluation of partial
molar properties.
07
(b) List out various methods for evaluation of fugacity coefficient of pure component.
Discuss any two in detail.
07

Q.2 (a) Explain Retrograde condensation in detail with figure. 07
(b) Show that for a binary system, Henry?s law is valid for component ?1? then Lewis
Randall rule is valid for component ?2?.
07
OR
(b) The enthalpy at 300 K and 1 bar of a binary liquid mixture is:
H = 400X1 + 600X2 + X1X2(40X1 + 20X2)where H is in J/mol for the stated temperature and pressure, determine: (i) Expression for partial molar enthalpies of both components 1 and 2, (ii) Numerical value for pure component enthalpies H1 and H2, (iii) Numerical values for the partial molar enthalpies for both the components at
infinite dilution.
07

Q.3 (a) Discuss various methods for checking the consistency of experimental VLE data.
07
(b) Explain T-x,y diagram for partially miscible system. 07
OR
Q.3 (a) At 300 K and 1 bar ,the volumetric data for a liquid mixture of benzene and
cyclohexane are represented by:
V=109.4 ? 10
-6
– 16.8 ?10
-6
x – 2.64 ?10
-6
x
2
where x is the mole fraction of benzene and V has the units of m
3
/mol. Find
expressions for the partial molar volumes of benzene and cyclohexane.
07
(b) Construct P-x-y diagram for the cyclohexane (1) / benzene (2) system at 313 K.
Use the following expressions for the liquid-phase activity coefficients:
ln ?1 = 0.458 x 2
2
, ln ?2 = 0.458 x 1
2
At 313 K, P 1
S
= 24.62 KPa and P 2
S
= 24.41 KPa.
07

Q.4 (a) Discuss the criteria of chemical reaction equilibrium. 07
(b) Discuss about the effect of temperature on equilibrium constant. 07
OR
Q.4 (a) Write short note on Van Laar equation and Margules equation. 07
(b) Discuss minimum and maximum boiling azeotropes giving examples for each
with neat diagrams.
07

Q.5 (a) In the synthesis of ammonia, stoichiometric amounts of nitrogen and hydrogen are
sent to a reactor where the following reaction occurs.
N2 + 3H2 ?2NH3
The equilibrium constant for the reaction at 675 K is 2 x 10
-4
. Determine the percent
conversion of nitrogen to ammonia at 675 K & 20 bar.
07
(b) Prove that ?G
0
= -RT lnK

07
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE – SEMESTER?V (OLD) – EXAMINATION ? SUMMER 2018
Subject Code:150503 Date:30/04/2018
Subject Name:Chemical Engineering Thermodynamics-II
Time:02:30 PM to 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define partial molar properties. Discuss various methods for evaluation of partial
molar properties.
07
(b) List out various methods for evaluation of fugacity coefficient of pure component.
Discuss any two in detail.
07

Q.2 (a) Explain Retrograde condensation in detail with figure. 07
(b) Show that for a binary system, Henry?s law is valid for component ?1? then Lewis
Randall rule is valid for component ?2?.
07
OR
(b) The enthalpy at 300 K and 1 bar of a binary liquid mixture is:
H = 400X1 + 600X2 + X1X2(40X1 + 20X2)where H is in J/mol for the stated temperature and pressure, determine: (i) Expression for partial molar enthalpies of both components 1 and 2, (ii) Numerical value for pure component enthalpies H1 and H2, (iii) Numerical values for the partial molar enthalpies for both the components at
infinite dilution.
07

Q.3 (a) Discuss various methods for checking the consistency of experimental VLE data.
07
(b) Explain T-x,y diagram for partially miscible system. 07
OR
Q.3 (a) At 300 K and 1 bar ,the volumetric data for a liquid mixture of benzene and
cyclohexane are represented by:
V=109.4 ? 10
-6
– 16.8 ?10
-6
x – 2.64 ?10
-6
x
2
where x is the mole fraction of benzene and V has the units of m
3
/mol. Find
expressions for the partial molar volumes of benzene and cyclohexane.
07
(b) Construct P-x-y diagram for the cyclohexane (1) / benzene (2) system at 313 K.
Use the following expressions for the liquid-phase activity coefficients:
ln ?1 = 0.458 x 2
2
, ln ?2 = 0.458 x 1
2
At 313 K, P 1
S
= 24.62 KPa and P 2
S
= 24.41 KPa.
07

Q.4 (a) Discuss the criteria of chemical reaction equilibrium. 07
(b) Discuss about the effect of temperature on equilibrium constant. 07
OR
Q.4 (a) Write short note on Van Laar equation and Margules equation. 07
(b) Discuss minimum and maximum boiling azeotropes giving examples for each
with neat diagrams.
07

Q.5 (a) In the synthesis of ammonia, stoichiometric amounts of nitrogen and hydrogen are
sent to a reactor where the following reaction occurs.
N2 + 3H2 ?2NH3
The equilibrium constant for the reaction at 675 K is 2 x 10
-4
. Determine the percent
conversion of nitrogen to ammonia at 675 K & 20 bar.
07
(b) Prove that ?G
0
= -RT lnK

07

2
OR
Q.5 (a) Write a brief note on Excess Properties. 07
(b) Discuss in detail: Ideal solutions and Non-ideal solutions.
07
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