Chemical Engineering Questions and Answers – Applications of Humidity Chart

This set of Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Applications of Humidity Chart”.

1. Which of the following is the humidity chart?
a) Psychrometric chart
b) Psychometric chart
c) Psychological chart
d) None of the mentioned
View answer

Answer: a
Explanation: Humidity chart is also called a Psychrometric chart.

2. Humidity chart relates which of the following balances?
a) Momentum and energy balance
b) Material and energy balance
c) Material and momentum balance
d) None of the mentioned
View answer

Answer: b
Explanation: Humidity chart relates material and energy balance.

3. In the humidity chart, what does the horizontal axis represent?
a) Air temperature
b) Dry-Bulb temperature
c) Wet-Bulb temperature
d) None of the mentioned
View answer

Answer: b
Explanation: The horizontal axis of humidity chart is dry-bulb temperature.
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4. Wet-bulb temperature is based on the equilibrium between rates of energy transfer to the bulb and which of the following?
a) Evaporation of water
b) Saturation of water
c) Freezing of water
d) None of the mentioned
View answer

Answer: a
Explanation: Wet-bulb temperature is based on the equilibrium between rates of energy transfer to the bulb and evaporation of water.

5. To plot the web-bulb line one information is wet-bulb temperature, what can be the other information?
a) Relative humidity
b) Dry-bulb temperature
c) Humidity
d) All of the mentioned
View answer

Answer: d
Explanation: Relative humidity, Dry-bulb temperature, or Humidity any of these can be the other information.

6. Which of the following is also called adiabatic cooling?
a) Humidification
b) Humidity
c) Humid temperature
d) None of the mentioned
View answer

Answer: a
Explanation: Humidification is also called adiabatic cooling.

7. What is the humidity at the point of intersection of the dew point curve and wet-bulb line?
a) Dry-bulb Humidity
b) Wet-bulb Humidity
c) Specific Humidity
d) None of the mentioned
View answer

Answer: a
Explanation: The humidity at the point of intersection of the dew point curve and wet-bulb line is called the wet-bulb humidity.
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8. What is the heat transferred from the system in the humidification process?
a) Positive
b) Negative
c) Zero
d) None of the mentioned
View answer

Answer: c
Explanation: Humidification is the adiabatic cooling process which means no heat exchange.

9. What happens to water in the humidification process?
a) Evaporates
b) Freezes
c) Saturated
d) None of the mentioned
View answer

Answer: a
Explanation: Water evaporates during the humidification process.
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10. What is the temperature of the point of intersection of adiabatic cooling line and specific humid volume line?
a) Wet-bulb temperature
b) Dry-bulb temperature
c) Dew point temperature
d) None of the mentioned
View answer

Answer: b
Explanation: The temperature of the point of intersection of adiabatic cooling line and specific humid volume line is the dry-bulb temperature.

11. What is the enthalpy change of the mixture if the enthalpy change of air is 10 J, enthalpy change of water vapor is 15 J, and the humidity is 40%?
a) 10 J
b) 12 J
c) 14 J
d) 16 J
View answer

Answer: d
Explanation: ∆H = ∆Hair + ∆Hwater(h) = 10 + 15*0.4 = 16 J.

12. What is the enthalpy change of 15oC system if the heat capacity of air at 20oC is 10 J/oC and heat capacity of water vapor at 20oC is 20 J/oC, enthalpy of vaporization is 20 J, and the humidity is 50%?
a) 50 J
b) 60 J
c) 80 J
d) 110 J
View answer

Answer: d
Explanation: ∆H = 10(20 – 15) + 0.5*[20(20 – 15) + 20] = 50 + 60 = 110 J.

13. What is the enthalpy change of 10oC system if the heat capacity of air at 20oC is 5 J/oC and heat capacity of water vapor at 20oC is 15 J/oC, enthalpy of vaporization is 10 J, and the humidity is 40%?
a) 58 J
b) 84 J
c) 114 J
d) 135 J
View answer

Answer: c
Explanation: ∆H = 5(20 – 10) + 0.4*[15(20 – 10) + 10] = 50 + 64 = 114 J.

14. What is the enthalpy change of 20oC system if the heat capacity of air at 25oC is 5 J/oC and heat capacity of water vapor at 25oC is 10 J/oC, enthalpy of vaporization is 10 J, and the humidity is 20%?
a) 25 J
b) 37 J
c) 44 J
d) 51 J
View answer

Answer: b
Explanation: ∆H = 5(25 – 20) + 0.2*[10(25 – 20) + 10] = 25 + 12 = 37 J.

15. What is the enthalpy change of 30oC system if the heat capacity of air at 38oC is 5 J/oC and heat capacity of water vapor at 38oC is 10 J/oC, enthalpy of vaporization is 10 J, and the humidity is 60%?
a) 14 J
b) 39 J
c) 65 J
d) 94 J
View answer

Answer: d
Explanation: ∆H = 5(38 – 30) + 0.6*[10(38 – 30) + 10] = 40 + 54 = 94 J.

Sanfoundry Global Education & Learning Series – Basic Chemical Engineering.

To practice all areas of Basic Chemical Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

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