Code No: R05310803 Set No. 1

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]

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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