(Calcutta University) BSc (Chemistry) II Practice Questions

CGT 22a

Unit I. Basic physical chemistry III

1.       What are the limitations of thermodynamics?

2.       What do you mean by state function and path function?

3.       State Zeroth law of thermodynamics?

4.       Explain why C_p is always greater than C_v ?

5.       Compare the magnitude of work of expansion of an ideal gas and a real gas?

6.       What is the relation between heat of reaction at constant pressure(q_p) volume (q_v).

7.       Derive the expression, w = C_v (T₂-T₁), for the work done for the adiabatic reversible expansion of an ideal gas.

8.       What is the thermodynamic basis of Hess’s law?

9.       Bomb calorimeter involves combustion in a closed vessel i.e. ∆V =0. Then ∆H = ∆U + P∆V should give ∆H + ∆U. Is it true? Why or why not?

10.   What is meant by efficiency of engine? Explain the terms, source and sink.

11.   Prove that in a reversible process not entropy change for the system and surroundings is zero.

12.   Write the expression for the efficiency of Carnot cycle in terms of work done, heat absorbed and temperatures of the source and sink.

13.    At absolute zero, the entropy of all pure elements and compounds is zero. Explain?

14.   Write the mathematical expression for the entropy change taking place in the working substance under each of the following circumstances.

(a)    Free expansion of 1 mole of an ideal gas from V₁ to V₂.

(b)   Reversible, isothermal phase transition.

(c)    Reversible adiabatic expansion of 1 mole of an ideal gas from V₁ to V₂.

(d)   Reversible isothermal expansion of 1 mole of an ideal gas from V₁ to V₂.

15.   Write Gibbs-Helmholtz equation.