Sunday, October 25, 2009


Code No: R05310803 Set No. 1
III B.Tech I Semester Regular Examinations, November 2007
(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 −
ln p2
sat/kpa = 14.0045 −
Prepare P-xy diagram for a temperature of 900C. [6+10]
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 = 1096104). [16

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