# JNTU previous year question papers B-Tech III Sem -Metallurgical thermodynamics and kinetics – Aug/Sep 2008

JNTU previous year question papers

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

Metallurgical thermodynamics and kinetics

(Metallurgy & Material Technology)

SET-1

1. (a) Explain the specific heats at constant volume and constant pressure.

(b) Explain why should specific heat not be defined interms of heat transfer.

(c) Explain how macro state is different from microstate.

2. (a) What is the maximum work obtainable from two finite bodies at temperatures T1 and T2? Explain.

(b) Explain the causes for the entropy increase.

(c) What is Hess law? Explain its applications in thermodynamics with suitable examples.

3. (a) Write down the first and second T.dS equations, and derive the expression for the difference in heat capacities, Cp and Cv. What does the expressions signify?

(b) At equilibrium of any reaction, explain the relationship between free energy change and equilibrium constant.

4. (a) Discuss the practical importance of Classius Clapeyron equation for liquid vapour equilibrium.

(b) Explain about Triple point or invariant point with an example.

(c) Discuss the importnce of Claussius Clapeyron equation.

5. What is lattice diffusion? Explain why activation energy is lower for lattice diffusion than diffusion along grain boundaries?

6. (a) Draw neatly the standard free energy of formation of many oxides as a function of temperature giving important reactions?

(b) What are the disadvantages of Richardson diagrams?

7. (a) Differentiate between regular solution and ideal solution?

(b) Al-Zn alloys exhibit the following relation at 477 0C RT ln ?Zn = 1750(1-XZn)2

where R and T are expressed in cal/deg/mole and K respectively. Calculate the activity of Al at 477 0C in Al-Zn alloy with 40 atom% Zn?

8. (a) A second order reaction has a initial concentration of the reactants of 0.4 moles/litre. The reaction is 30 percent complete in 80 min, calculate the rate constant and the time it would take for the reaction to be 80 percent complete?

(b) Derive an expression for the rate constant and half life method?