# Chemical Process Calculation Questions and Answers – Enthalpy – II

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This set of Chemical Process Calculation Multiple Choice Questions & Answers (MCQs) focuses on “Enthalpy – II”.

1. What is the Enthalpy change for a 10 Kg mole Oxygen gas that is heated from 200 K to 400 K at constant pressure. (Cv = 40000 J/(Kg*mole)*(Degree Celsius))
a) 20*106
b) 40*106
c) 60*106
d) 80*106

Explanation: H2 – H1 = nCp(T2-T1).

2. What is the Enthalpy change for a 20 Kg mole Nitrogen gas that is heated from 100 K to 200 K at constant pressure. (Cv = 2000 J/(Kg*mole)*(Degree Celsius))
a) 2*106
b) 4*106
c) 6*106
d) 8*106

Explanation: H2 – H1 = nCp(T2-T1).

3. The negative of heat of vaporization is
a) Heat of Condensation
b) Heat of fusion
c) Heat of solidification
d) Heat of sublimation

Explanation: The negative of heat of vaporization is Heat of Condensation.

4. The Enthalpy change for the phase transition of melting is ___________
a) Heat of Condensation
b) Heat of fusion
c) Heat of solidification
d) Heat of sublimation

Explanation: The Enthalpy change for the phase transition of melting is the Heat of fusion.

5. The negative of the heat of fusion is
a) Heat of Condensation
b) Heat of vaporization
c) Heat of solidification
d) Heat of sublimation

Explanation: The negative of the heat of fusion is Heat of solidification.

6. The Enthalpy change of a solid directly to vapour is __________
a) Heat of Condensation
b) Heat of vaporization
c) Heat of solidification
d) Heat of sublimation

Explanation: The Enthalpy change of a solid directly to vapour is the Heat of sublimation.

7. The enthalpy change for the phase transition of a liquid to a vapour is
a) Heat of Condensation
b) Heat of vaporization
c) Heat of solidification
d) Heat of sublimation

Explanation: The enthalpy change for the phase transition of a liquid to a vapour is called Heat of vaporization.

8. An example of phase transition is
a) Liquid to gas phase
b) Gas to liquid phase
c) Solid to liquid phase
d) All of the mentioned

Explanation: Phase change is occurring in each case.

9. An enthalpy change that involve a phase transition is
a) Heat of the reaction
b) Latent Heat
c) Heat of fusion
d) Heat of sublimation

Explanation: An enthalpy change that involve a phase transition is Latent heat.

10. An enthalpy change that does not involve a phase transition is
a) Latent Heat
b) Sensible Heat
c) Heat of solidification
d) Heat of sublimation 