JNTU Question Papers Chemical and Bio-Thermodynamics I-Sem Nov 2008

JNTU Question Papers

Chemical and Bio-Thermodynamics I-Sem Nov 2008



1. A gas is confined in a cylinder by a piston, 2 in. in diameter, on which rests

a “weight”. The mass of the piston and weight together is 8 lbm. The local

acceleration of gravity is 32.00 ft/sec2. Assume standard atmospheric pressure.

(a) What is the force exerted on the gas by the atmosphere, the piston, and the

weight in pounds force, assuming no friction between the piston and cylinder?

(b) What is the pressure of the gas in pounds force per square inch?

(c) If the gas in the cylinder is heated, it will expand, pushing the piston and

weight upward. Assuming that enough heat is supplied to raise the piston

and weight 8 in., calculate the work done by the gas in raising the piston and

weight. What is the change in potential energy of the piston and weight? Give

your answers in foot-pounds force. [4+4+8]


2. Steam is flowing through a horizontal, well-insulated 3-in. – ID iron pipe, 1500 ft

long. The velocity at the entrance to the pipe, where the steam is dry and saturated

at 150 psia, is 100 ft/sec. The steam discharges from the exit of the pipe into an

adiabatic reversible turbine which exhausts at 14.7 psia. The steam leaving the

turbine is in the dry-saturated condition.

(a) Calculate the horsepower produced by the turbine.

(b) Represent by a sketch on T-S plane the change in the state of the steam as it

flows through the pipe and the turbine.

(c) What is the state of the steam entering the turbine? [6+6+4]


3. Estimate V, U, H and S for 1-butene vapor at 2000C and 70 bar, is H and S are set

equal to zero for saturated liquid at 00C. The only data available are: TC = 420.0

K; PC = 40.43 bar; Normal boiling Point = 266.9 K; Acentric factor = 0.191; CigP

/R = 1.961 + 31.630 x 10?3 T – 9.837 x 10?6 T2

Interpolated values of Z0 and Z1 of the acentric factor based correlation, corre-

sponding to TR = 1.127 and PR = 1.731 are 0.485 and 0.142 respectively. [16]


4. (a) Write briefly about fugacity and fugacity coefficient for a pure species

(b) Derive the expression for Poyinting factor [8+8]


5. The Stability criteria apply to a particular phase. However, there is nothing to

preclude their application to problems in phase equilibria,where the phase of interest

(e.g; a liquid mixture) is in equilibrium with another phase (e.g; a vapour mixture).

Considerbinary isothermal vapour/liquid equilibria at pressures low enough that the

vapour phase may be considered an ideal-gas mixture.what are the implications of

liquid-phase stability to the features of isothermal P-X-Y diagrams. [16]


6. (a) Describe the effect of temperature on reaction equilibrium constant .

(b) Is the following reaction promising as a method of manufacture for sodium


NaOH(s) + CO(g) ??HCOONa (s)

The following are the data on F0 [8+8]


Component       F0, keal/g mole

CO(g)                   -32.808

NaOH(s)               -90.60

HCOONa(s)          -147.0


7. (a) Explain the Gaden classification from stoichiometric point of view the product

formation in fermentation processes.

(b) The following stoichiometric equation describes penicillin systhesis

1.5Glucose+H2SO4+2NH3 + phenyl acetate! Pencillium G + CO2+8H2O

the theoretical yield of pencillium is 1.2g/(gram of glucose). Find out the

molecular weight of pencillium G. [8+8]


8. (a) The growth of the yeast, Saccharomyces cerevisiae can be given by the follow-

ing overall stoichiometry equation

C6H12O6(aq) + 0.188NH3! 0.590 CH1.737N0.2O0.451+ 0.432 C H3 H8O3

+1.54 C02(aq) + 1.30 C2H50H (aq) + 0.036 H20 (1)

_G0= – 167.9 MJ/Kmol.

Give a schematic representation of the fermentation process.

(b) Humid air enriched with oxygen is prepared for gluconic acid fermentation.

The air is prepared in a special humidifying chamber 1.5 lit/h liquid waterenters the chamber at the same time as dry air, and 15 g-moles/min dry oxygen gas. All the water is evaporated. The out flowing gas is found to contain 1% (w/w) of water. Draw and label the flow sheet for the process.


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