CHEMICAL ENGINEERING THERMODYNAMICS-II JNTU UNIVERSITY PREVIOUS YEAR QUESTION PAPER COLLECTION

CHEMICAL ENGINEERING THERMODYNAMICS-II JNTU UNIVERSITY PREVIOUS YEAR QUESTION PAPER COLLECTION

CHEMICAL ENGINEERING THERMODYNAMICS-II JNTU UNIVERSITY PREVIOUS YEAR QUESTION PAPER COLLECTION

III B.Tech I Semester Regular Examinations, November 2007

CHEMICAL ENGINEERING THERMODYNAMICS-II

(Chemical Engineering)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

⋆ ⋆ ⋆ ⋆ ⋆

1. (a) The latent heat of vaporization of ethyl alcohol is experimentally to be 200
cal/gm. at its normal BP of 78 0C. Its critical temperature is 243 oC. Estimate
the heat of vaporization at a temperature of 180 oC.
(b) Define of heat of solution based on one mole of solution and one mole of solute.
Also derive the relationship between them. [6+10]
2. The gas stream from a sulphur burner is composed of 45 mol % SO2, and 55 mol%
O2. This gas stream at 1 bar and 480 oC enters a catalytic converter when SO2
is further oxidized to SO3. Assuming that the reaction reaches equilibrium, deter-
mine how much heat must be removed from the converter to maintain isothermal
conditions per 100 mol of entering gas Cp / R = A + BT +D/T2 [16]
A 103 B 10−5 D Hf, 25oC Gof, 25oC
J/mol J/mol
SO2 5.699 0.801 -1.015 -296830 -300194
O2 3.639 0.506 -0.227 - - - - - - - - - -
SO3 8.060 1.056 -2.028 -395720 -371060
3. (a) Discuss the determination of fugacity from equation of state, with special
reference to Vander waals gas and show that, ln f = ln (RT/(V-b)) + b/(V-b)
? 2a/RTV.
(b) Show mathematically that the entropy change on mixing is not zero even for
ideal gases. [12+4]
4. (a) Elucidate the vapor-liquid equilibrium of binary systems with the help of p-x-y
and t-x-y diagrams.
(b) Write and explain models for excess Gibbs energy based on the local compo-
sition. [12+4]
5. (a) Discuss the phase rule and Duhem’s theorem for non-reacting system, explain
in detail.
(b) The binary system of benzene (1) / ethyl benzene (2) conforms closely to
Raoult’s law. Vapor pressures for the pure species are given by the following
Antoine equations:
ln p1
sat/kpa = 13.8594 −
2773.78
t/0C+220.07
ln p2
sat/kpa = 14.0045 −
3279.47
t/0C+213.2
Prepare P-xy diagram for a temperature of 900C. [6+10]
1 of 2
Code No: R05310803 Set No. 1
6. Determine expressions for GR, HR, SR implied by the vander waals equation of
state. [16]


7. Develop equations that apply to the limiting case of binary LLE for which the
α-phase is very dilute in spices 1 and the β-phase is very dilute in species2. [16]
8. A mixture of N2, H2 and Argon in the mole ratio 1:3:2 enters a catalytic reactor
for the synthesis of ammonia. The reactor is maintained at 400oC and 20 Mpa.
Estimate the degree of conversion (K = 1096 104). [16]
⋆ ⋆ ⋆ ⋆ ⋆

III B.Tech I Semester Regular Examinations, November 2007

CHEMICAL ENGINEERING THERMODYNAMICS-II

(Chemical Engineering)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

⋆ ⋆ ⋆ ⋆ ⋆

1. If the heat capacity of the substance is correctly represented by in equation of the
form, Cp = A + BT + CT2
Show that the error resulting when <Cp>H is assumed = Cp evaluated at the
arithmetic mean of initial and final temperature is C(T2 − T1)2/12. [16]
2. Calculate the maximum temperature in degree centigrade when the following gas
is burned with 30% excess air entering at 25 0C:
CO 30%
H2 15%
CO2 5%
N2 50%
The mean heat capacities of these gages (in cal/ g mole 0K) are:
CO : 7.587
H2 : 7.138
O2 : 7.941
N2 : 7.507
CO2 :11.92
H2O : 9.39
Heat of combustion data: Hc (k cal/ g mole) CO = 67.63 and H2O = 68.32. [16]
3. Derive the relation for the calculation of Gibbs free energy of ideal gas mixture,
starting from fundamental property relation. [16]
4. Vapor-liquid equilibrium data for the system 1, 2 dichloro methane (1) /methanol
(2) at 50 oC are as follows:
P/kpa x1 y1
55.55 0.000 0.000
58.79 0.042 0.093
64.59 0.189 0.265
65.76 0.349 0.349
65.59 0.415 0.367
63.86 0.632 0.418
59.03 0.835 0.484
48.41 0.945 0.620
31.10 1.000 1.000
1 of 2
Code No: R05310803 Set No. 2
Determine the values of lnγ1 and lnγ2 using Margules equations. Also plot lnγ1 and
lnγ2 Vs x1. [16].
5. The excess Gibbs energy for a binary system is given by: GE/ RT = 0.45 X1 X2.
The pure component vapor pressures are given by:
ln P1
sat/kPa = 14.39−
2795.8
t/oC+230
ln P2
sat/kPa = 16.59−
3644.2
t/oC+239
Obtain the P-x, y diagram for this system at 50oC. [16]
6. Show that the residual Gibbs energy of fluids from Redlich-Kwong equation of state
is GR
RT = Z − 1 − ln(1 − h)Z −