Chemical Process Calculation Multiple Choice Questions & Answers (MCQs) focuses on “Energy Balances – Heat”.
1. Heat transfer can occur by
a) Conduction
b) Convection
c) Radiation
d) All of the mentioned
Answer: d
Clarification: Conduction, Convection and Radiation are the usually as the three categories of heat transfer.
2. Two state are given as following
I: Heat is a substance
II: Heat is proportional to temperature
a) Both I and II are correct
b) Both I and II are incorrect
c) Only I is correct
d) Only II is correct
Answer: b
Clarification: Heat is not a substance and It is not mandatory for heat to be proportional to temperature.
3. Heating always results in an increase in temperature. The statement is
a) Correct
b) Incorrect
c) Always correct
d) None of the mentioned
Answer: b
Clarification: Heating always does not result in an increase in temperature.
4-8. Q = UA(T2-T1); A formula for heat transfer is given
where: Q – Rate of Heat transfer
U – Empirical constant
(T2-T1) – Temperature difference between surrounding and system
4. When Q < 0
a) Heat is transferred from system
b) Heat is transferred from surrounding
c) Heat is gained by system
d) None of the mentioned
Answer: a
Clarification: Q < 0, means T2-T1 < 0; Heat is transferred from system.
5. When Heat is gained by the system
a) Q < 0
b) Q > 0
c) Q = 0
d) None of the mentioned
Answer: b
Clarification: Heat transferred from the surrounding, T2-T1> 0 so Q > 0.
6. When Q = 0, there is possibility that
a) Temperature of system and surrounding are same
b) System is an adiabatic system
c) Both a and b
d) Neither a nor b
Answer: c
Clarification: For Q = 0, System may be insulated or there is no temperature difference.
7. If Q = 45 W and The values of U and A are 10 and 2.5 with their respective SI units. What is the temperature difference between system and surrounding?
a) 1.8 Degree Celsius
b) 1.8 Degree Fahrenheit
c) 1.8 Degree Rankine
d) None of the mentioned
Answer: a
Clarification: T2-T1 = 1.8 Degree Celsius, Q = UA(T2-T1).
8. Q = 45 means
a) Heat is transferred from the system
b) Heat is transferred from surrounding
c) Heat is gained by the surrounding
d) None of the mentioned
Answer: b
Clarification: Q > 0,Heat is gained by the system and transferred from the surrounding.
9. A cold body contains no heat. The statement is
a) Correct
b) Incorrect
c) Always correct
d) None of the mentioned
Answer: b
Clarification: Heat can be contained by a cold body.
10. Heat can travel only
a) Upwards
b) Downwards
c) Upwards and Downwards
d) None of the mentioned
Answer: d
Clarification: It is not mandatory to travel in only in upward an downward direction.