# JNTU previous year question papers B.Tech I Semester -Metallurgical thermodynamics and kinetics – November 2008

JNTU II B.Tech I Semester Regular Examinations, November 2008

Metallurgical thermodynamics and kinetics

(Metallurgy & Material Technology)

SET-3

1. (a) Show that for an ideal gas the internal energy depends only on its temperature.

(b) What does the subject thermodynamics deal with?

(c) Explain the relation between internal energy, heat and work done for a system.

2. (a) Derive expressions for variation of entropy during reversible isothermal processes.

(b) Show that for an irreversible process T.dS > ?qir.

3. (a) Explain the necessity of Maxwell’s relations:

(b) The vapour pressure of pure solid silver and solid silver-palladium are given in the following: For silver: log p = ?13,700 T + 8.73

For solid silver-palladium alloy at NAg=0.8

log P=-13,800/T+8.65.

Calculate the activity coefficient of silver in the alloy.

4. (a) Derive the Clausius-Clapeyron equation.

(b) For the estimation of vapour pressure of an element/compound, which rule is

a valuable empirical aid. Explain the rule in detail.

5. Explain the following:

(a) Self diffusion in pure metals

(b) Temperature dependence of the diffusion coefficient.

6. Define the following:

(a) Equilibrium Constant

(b) Free Energy

(c) Activity Coefficient

(d) Equilibrium Diagram.

(a) Composition of a binary solution

(b) Activity Coefficient

(c) Molal Quantities

(d) Gibb’s Margules Equation.

8. (a) Derive an equation for specific reaction rate constant of a reaction from theory

of absolute reaction rates?

(b) Calculate the rate of decarburization in % per hr for a steel bath 40cm deep in an open hearth furnace from the following data:

i. Difference between the oxygen content at the slag metal interface and the main bath = 0.04%

ii. Thickness of the metal film rich in oxygen = 0.004cm

iii. Diffusivity of oxygen = 2×10?4 cm2/sec.