250+ TOP MCQs on Humidity (Psychrometric) Chart and Answers

Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) on “Humidity (Psychrometric) Chart”.

1. What is the specific humidity, if the mass of water is 10 g and mass of bone dry air is 20 g?
a) 10%
b) 30%
c) 50%
d) 80%

Answer: c
Clarification: H = 10/20*100 = 50%.

2. What is the specific humidity, if the mass of water is 15 g and mass of bone dry air is 25 g?
a) 10%
b) 30%
c) 40%
d) 60%

Answer: d
Clarification: Specific humidity = 15/25*100 = 60%.

3. What is the specific humidity, if pressure of water is 5 atm and total pressure is 10 atm?
a) 25%
b) 50%
c) 75%
d) 100%

Answer: d
Clarification: Specific humidity = 5/(10 – 5)*100 = 100%.

4. What is the specific humidity, if pressure of water is 2 atm and total pressure is 12 atm?
a) 20%
b) 40%
c) 50%
d) 80%

Answer: d
Clarification: Specific humidity = 2/(12 – 2)*100 = 20%.

5. What is the specific humidity, if moles of water are 4 and total moles are 5?
a) 20%
b) 80%
c) 200%
d) 400%

Answer: d
Clarification: Specific Humidity = 4/(5 – 4)*100 = 400%.

6. What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 20 J), if the humidity is 25%?
a) 10 J
b) 15 J
c) 20 J
d) 25 J

Answer: b
Clarification: CS = 10 + 20*0.25 = 15 J.

7. What is the humid heat of a mixture of air (CP = 20 J) with water vapor (CP = 30 J), if the humidity is 40%?
a) 24 J
b) 32 J
c) 38 J
d) 44 J

Answer: b
Clarification: CS = 20 + 30*0.4 = 32 J.

8. What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 15 J), if the humidity is 40%?
a) 16 J
b) 20 J
c) 24 J
d) 32 J

Answer: a
Clarification: CS = 10 + 15*0.4 = 16 J.

9. What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 15 J), if the humidity is 60%?
a) 10 J
b) 14 J
c) 19 J
d) 23 J

Answer: c
Clarification: CS = 10 + 15*0.6 = 19 J.

10. What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 25 J), if the humidity is 20%?
a) 15 J
b) 20 J
c) 25 J
d) 30 J

Answer: a
Clarification: CS = 10 + 25*0.2 = 15 J.

11. Which of the following is the summation of a volume of 1 Kg of dry air and the water vapor in the air?
a) Humid volume
b) Partial volume
c) Dry volume
d) None of the mentioned

Answer: a
Clarification: Humid volume is the summation of a volume of 1 Kg of dry air and the water vapor in the air.

12. What is the humid volume of the system at 100oF with humidity 20%?
a) 18.6 ft3/lb
b) 22.4 ft3/lb
c) 26.5 ft3/lb
d) 29.4 ft3/lb

Answer: a
Clarification: V = (0.73T + 336)(1/29 + H/18) = (0.73*100 + 336)(1/29 + 0.2/18) = 18.6 ft3/lb.

13. What is the humid volume of the system at 200oF with humidity 40%?
a) 14.2 ft3/lb
b) 23.4 ft3/lb
c) 29.5 ft3/lb
d) 31.6 ft3/lb

Answer: d
Clarification: V = (0.73*200 + 336)(1/29 + 0.4/18) = 31.6 ft3/lb.

14. What is the humid volume of the system at 150oF with humidity 50%?
a) 12.4 ft3/lb
b) 19.5 ft3/lb
c) 27.7 ft3/lb
d) 36.1 ft3/lb

Answer: c
Clarification: V = (0.73*150 + 336)(1/29 + 0.5/18) = 27.7 ft3/lb.

15. What is the humid volume of the system at 300oF with humidity 30%?
a) 15.5 ft3/lb
b) 28.4 ft3/lb
c) 39.8 ft3/lb
d) 55.2 ft3/lb

Answer: b
Clarification: V = (0.73*300 + 336)(1/29 + 0.3/18) = 28.4 ft3/lb.