This set of Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Simplifications of General Energy Balance”.
1. What is the work done by an open steady-state system if heat transferred to it is 10 J?
a) 0
b) -10 J
c) 10 J
d) Cannot be determined
View answer
Explanation: In steady state system ∆E = 0, => Work done by the system = 10 J.
2. In a closed system, change in internal energy is 10 J and heat transferred to it is 10 J what is the work done by the system?
a) 0
b) 10 J
c) -20 J
d) 20 J
View answer
Explanation: ∆E = W + Q, => W = 10 – 10 = 0.
3. In an open system, what is the enthalpy change is heat taken from it is 10 J?
a) 0
b) -10 J
c) 10 J
d) Cannot be determined
View answer
Explanation: For an open system, ∆H = Q, => ∆H = -10 J.
4. In an open, steady state adiabatic process if the change in kinetic energy is 10 J and change in potential energy is 15 J, what is the work done by the system?
a) 10 J
b) 15 J
c) 25 J
d) -25 J
View answer
Explanation: -W = ∆KE + ∆PE = 10 + 15 = 25, => W = -25 J.
5. In an open, steady state system if the heat transferred is 10 J and work done by the system is 5 J, what is the change in Potential energy (neglect kinetic energy)?
a) 5 J
b) -5J
c) 15 J
d) -15 J
View answer
Explanation: W + Q = ∆PE, => ∆PE = 10 – 5 = 5 J.
6. Which of the following is true for isothermal ideal gases?
a) ∆T = 0
b) ∆U = 0
c) ∆H = 0
d) All of the mentioned
View answer
Explanation: For isothermal ideal gases, ∆T = 0, => ∆U = 0, => ∆H = 0.
7. If the system is insulated which of the following might the process be?
a) Isothermal
b) Isobaric
c) Isochoric
d) Adiabatic
View answer
Explanation: Since the system is insulated, => Q = 0, => Process is adiabatic.
8. What is the work done for an isochoric process?
a) Positive
b) Negative
c) Zero
d) Cannot say
View answer
Explanation: W = -PdV, for isochoric process dV = 0, => W = 0.
9. What is the work done for an ideal gas isothermal process?
a) Zero
b) Equal to heat transferred
c) Equal to change in internal energy
d) Cannot say
View answer
Explanation: For ideal gas isothermal process ∆U = 0, => Work done is equal to heat transferred.
10. What is the work done for an isobaric process?
a) P∆V
b) V∆P
c) PV
d) None of the mentioned
View answer
Explanation: For isobaric process ∆P = 0, => W = P∆V.
11. For an ideal gas isobaric process at pressure 1 Pa, the volume of the gas changes from 1 m3 to 5 m3, what is the work done by the gas?
a) 1 J
b) 4 J
c) 5 J
d) 10 J
View answer
Explanation: W = P∆V = 1*(5 – 1) = 4 J.
12. For an ideal gas isothermal process what is the work done by the gas from 1 m3 to 2 m3 at 300 K?
a) 0.69 kJ
b) 1.24 kJ
c) 1.73 kJ
d) 2.45 kJ
View answer
Explanation: W = RTln (V2/V1) = 8.314*300 ln (2/1) = 1.73 kJ.
13. For an ideal gas isothermal process what is the work done by the gas from 4 Pa to 1 Pa at 300 K?
a) 1.22 kJ
b) 2.15 kJ
c) 2.83 kJ
d) 3.45 kJ
View answer
Explanation: W = RTln (P1/P2) = 8.314*300 ln (4/1) = 3.45 kJ.
14. For an ideal gas isochoric process, what is the work done by the gas from 2 Pa to 1 Pa?
a) 0
b) 1 J
c) 200 J
d) None of the mentioned
View answer
Explanation: Since the process is isochoric, => W = 0.
15. For an ideal gas isobaric process what is the work done by the gas from 2 m3 to 0.5 m3 at 2 Pa?
a) -3 J
b) 3 J
c) -5 J
d) 5 J
View answer
Explanation: Work done by the gas = 2*(0.5 – 2) = -3 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.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
