Engineering Chemistry S Datta

100 ENGINEERING CHEMISTRY
Q. 16. Define C p
and C v
. State relation between them.
Ans. See page 73.
Q. 17. Explain that Joule-Thomson experiment is isoenthalpic.
Ans. See page 71.
Q. 18. What is inversion temperature?
Ans. See page 72.
Q. 19. State with example the significance of Hess’s law.
Ans. See page 81.
Q. 20. State the law of Laplace and Lavoisier.
Ans. See page 80.
Q. 21. Define (a) heat of formation, (b) heat of combustion, (c) heat of
neutralisation.
Ans. See page 81, 82.
Q. 22. State the second law of thermodynamics.
Ans. See page 84. Alternatively it can be stated as the net entropy of the universe tends
to a maximum.
at 25°C?
Q. 23. What do you mean by a cyclic process?
Ans. See page 70.
Q. 24. State Maxwell’s relations.
Ans. See page 89.
Q. 25. Define work function and free energy.
Ans. See pages 78 and 79.
Q. 26. How can you measure a spontaneous system with the help of free energy?
Ans. See text page 79.
Q. 27. What do you mean by ∆G° for the reaction H 2
+ 1 2 O 2 = H 2O is – 54.65 Kcal
Ans. It means that if a mole of H 2
and 1 2 mole of O 2
both at unit pressures at constant
temperature (25°C), the decrease in free energy is 54.65 Kcal.
EXERCISES
1. Short Questions:
(i) Derive an expression for the variation of heat of reaction with the temperature with the help
of first law of thermodynamics.
(ii) Derive Clapeyron-Clausius equation and state its applications.
(iii) Define the concepts of Helmholtz free energy and Gibb’s free energy. Describe a relation between
the two.
(iv) What is the significance of entropy? What is the criteria for spontaneity?
(v) Derive Kirchoff’s equation. It is based on which law? Explain.