Laws of Heat, Energy, and Entropy: MCQ Set for Liberty
University
(Including Applications to Physical Systems and Mathematical
Problems)
1. Which law of thermodynamics states that energy cannot be created or destroyed?
a) Zeroth law
b) First law
c) Second law
d) Third law
Answer: b) First law
2. The concept of absolute zero temperature is related to which law of thermodynamics?
a) Zeroth law
b) First law
c) Second law
d) Third law
Answer: d) Third law
3. What does the zeroth law of thermodynamics establish?
a) Conservation of energy
b) Increase of entropy
c) Thermal equilibrium
d) Absolute zero temperature
Answer: c) Thermal equilibrium
4. Which of the following is NOT a statement of the second law of thermodynamics?
a) Heat flows spontaneously from hot to cold
b) Entropy of an isolated system always increases
c) No process is 100% efficient
d) Energy is conserved in all processes
Answer: d) Energy is conserved in all processes
5. In a cyclic process, the change in internal energy of a system is:
a) Always positive
b) Always negative
c) Zero
d) Depends on the process
Answer: c) Zero
6. What is the SI unit of entropy?
a) Joule (J)
b) Kelvin (K)
c) Joule per Kelvin (J/K)
d) Watt (W)
Answer: c) Joule per Kelvin (J/K)
7. A heat engine operates between reservoirs at 400 K and 300 K. What is its maximum
theoretical efficiency?
a) 15%
b) 25%
c) 33%
d) 75%
Answer: b) 25%
8. Which of the following is an intensive property?
a) Mass
b) Volume
c) Temperature
d) Internal energy
Answer: c) Temperature
9. The Clausius statement of the second law of thermodynamics relates to:
a) Heat flow direction
b) Efficiency of heat engines
c) Entropy increase
d) Conservation of energy
Answer: a) Heat flow direction
10. What is the change in entropy when 100 J of heat is added to a system at a constant
temperature of 300 K?
a) 0.33 J/K
b) 3 J/K
c) 30,000 J/K
d) 0.003 J/K
Answer: a) 0.33 J/K
11. Which of the following processes always results in an increase of entropy?
a) Isothermal compression
b) Adiabatic expansion
c) Isobaric cooling
d) Irreversible process
Answer: d) Irreversible process
12. The Kelvin-Planck statement of the second law of thermodynamics is related to:
a) Heat flow direction
b) Efficiency of heat engines
c) Entropy increase
d) Conservation of energy
Answer: b) Efficiency of heat engines
13. In an adiabatic process, which of the following remains constant?
a) Temperature
b) Pressure
c) Volume
d) Heat
Answer: d) Heat
14. What is the efficiency of a Carnot engine operating between 500 K and 300 K?
a) 20%
b) 40%
c) 60%
d) 80%
Answer: b) 40%
15. The concept of enthalpy is most useful in which type of process?
a) Isochoric
b) Isobaric
c) Isothermal
d) Adiabatic
Answer: b) Isobaric
16. What is the change in internal energy when 500 J of heat is added to a system and 200 J of
work is done by the system?
a) 300 J
b) 700 J
c) -300 J
d) -700 J
Answer: a) 300 J
17. Which of the following is TRUE for a reversible process?
a) It can occur spontaneously
b) It results in maximum work
c) It increases entropy
d) It is fastest
Answer: b) It results in maximum work
18. The Gibbs free energy is defined as:
a) G = H + TS
b) G = H - TS
c) G = U + PV
d) G = U - TS
Answer: b) G = H - TS
19. In an isothermal expansion of an ideal gas, which of the following is TRUE?
a) Temperature increases
b) Internal energy increases
c) Work is done by the gas
d) Heat is released to the surroundings
Answer: c) Work is done by the gas
20. A heat pump has a coefficient of performance of 3. If it delivers 3000 J of heat to a room,
how much work does it require?
a) 750 J
b) 1000 J
c) 3000 J
d) 9000 J
Answer: b) 1000 J
21. Which of the following is NOT a statement of the third law of thermodynamics?
a) Entropy approaches a constant value as temperature approaches absolute zero
b) It is impossible to reach absolute zero in a finite number of steps
c) The entropy of a perfect crystal at absolute zero is zero
d) Heat always flows from hot to cold
Answer: d) Heat always flows from hot to cold
22. What is the change in entropy when 1 kg of ice at 0°C melts to water at 0°C? (Latent heat of
fusion of ice = 334 kJ/kg)
a) 0.122 kJ/K
b) 1.22 kJ/K
c) 12.2 kJ/K
d) 122 kJ/K
Answer: b) 1.22 kJ/K
23. Which of the following is an example of an extensive property?
a) Density
b) Specific heat
c) Volume
d) Temperature
Answer: c) Volume
24. The work done by an ideal gas expanding isothermally from volume V1 to V2 is given by:
a) W = P(V2 - V1)
b) W = nRT ln(V2/V1)
c) W = nCV(T2 - T1)
d) W = nCP(T2 - T1)
Answer: b) W = nRT ln(V2/V1)
25. Which of the following processes has the highest entropy change for an ideal gas?
a) Isothermal expansion
b) Adiabatic expansion
c) Isobaric expansion
d) Isochoric heating
Answer: c) Isobaric expansion
26. What is the efficiency of a heat engine that absorbs 1000 J of heat and rejects 600 J of heat
in each cycle?
a) 20%
b) 40%
c) 60%
d) 80%
Answer: b) 40%
27. The internal energy of an ideal gas depends only on its:
a) Pressure
b) Volume
c) Temperature
d) Entropy
Answer: c) Temperature
28. In a free expansion of an ideal gas, which of the following remains constant?
a) Temperature
b) Pressure
c) Internal energy
d) Entropy
Answer: c) Internal energy
29. What is the change in entropy when 2 moles of an ideal gas expands isothermally from 1 L
to 10 L? (R = 8.314 J/mol·K)
a) 19.14 J/K
b) 38.29 J/K
c) 57.43 J/K
d) 76.58 J/K
Answer: b) 38.29 J/K
30. Which of the following is TRUE for a spontaneous process?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) ΔG has no relation to spontaneity
Answer: b) ΔG < 0
31. The specific heat capacity of a substance is defined as:
a) The heat required to raise the temperature of 1 kg by 1 K
b) The heat required to raise the temperature of 1 mol by 1 K
c) The heat required to raise the temperature of 1 g by 1 K
d) The heat required to raise the temperature of the substance by 1 K
Answer: a) The heat required to raise the temperature of 1 kg by 1 K
32. Which of the following is TRUE for an adiabatic process of an ideal gas?
a) PV = constant
b) TV^(γ-1) = constant
c) PV^γ = constant
d) PT^(1-γ) = constant
Answer: c) PV^γ = constant
33. The Joule-Thomson effect is observed during:
a) Isothermal expansion
b) Adiabatic expansion
c) Throttling process
d) Isobaric heating
Answer: c) Throttling process
34. What is the work done when a gas expands from 2 L to 5 L against a constant external
pressure of 1 atm?
a) 3 L·atm
b) -3 L·atm
c) 10 L·atm
d) -10 L·atm
Answer: b) -3 L·atm
35. Which of the following is NOT a property of a reversible process?
a) Quasi-static
b) Infinitesimally close to equilibrium
c) Path-independent
d) Maximum work output
Answer: c) Path-independent
36. The change in entropy of the universe for a reversible process is:
a) Positive
b) Negative
c) Zero
d) Undefined
Answer: c) Zero
37. What is the efficiency of a heat engine operating between 127°C and 27°C?
a) 20%
b) 25%
c) 30%
d) 35%
Answer: b) 25%
38. Which of the following is TRUE for a cyclic process?
a) ΔU = 0
b) Q = W
c) ΔS = 0
d) Both a and b
Answer: d) Both a and b
39. The Helmholtz free energy is defined as:
a) A = U + TS
b) A = U - TS
c) A = H + PV
d) A = H - PV
Answer: b) A = U - TS
40. What is the change in entropy when 100 g of water at 100°C is converted to steam at
100°C? (Latent heat of vaporization of water = 2257 J/g)
a) 0.605 J/K
b) 6.05 J/K
c) 60.5 J/K
d) 605 J/K
Answer: d) 605 J/K
41. Which of the following is an intensive property?
a) Heat capacity
b) Enthalpy
c) Specific heat capacity
d) Internal energy
Answer: c) Specific heat capacity
42. The work done in an adiabatic process of an ideal gas is equal to:
a) ΔU
b) -ΔU
c) Q
d) -Q
Answer: b) -ΔU
43. What is the change in internal energy when 500 J of heat is added to a system and 200 J of
work is done on the system?
a) 300 J
b) 700 J
c) -300 J
d) -700 J
Answer: b) 700 J
44. Which of the following is TRUE for an ideal gas?
a) CP = CV
b) CP > CV
c) CP < CV
d) CP and CV are not related
Answer: b) CP > CV
45. The coefficient of performance of a refrigerator is defined as:
a) QH / W
b) QC / W
c) W / QH
d) W / QC
Answer: b) QC / W
46. What is the change in entropy when 1 kg of water at 20°C is heated to 80°C? (Specific heat
capacity of water = 4186 J/kg·K)
a) 180 J/K
b) 836 J/K
c) 1672 J/K
d) 3348 J/K
Answer: b) 836 J/K
47. Which of the following is TRUE for a spontaneous process?
a) ΔSuniverse > 0
b) ΔSuniverse < 0
c) ΔSuniverse = 0
d) ΔSuniverse has no relation to spontaneity
Answer: a) ΔSuniverse > 0
48. The internal energy of an ideal gas is given by:
a) U = 3/2 nRT (monatomic)
b) U = 5/2 nRT (diatomic)
c) U = 3 nRT (polyatomic)
d) All of the above, depending on the gas
Answer: d) All of the above, depending on the gas
49. Which of the following processes has zero change in enthalpy for an ideal gas?
a) Isothermal expansion
b) Adiabatic expansion
c) Free expansion
d) Isobaric expansion
Answer: c) Free expansion
50. What is the work done by 2 moles of an ideal gas expanding isothermally from 1 L to 10 L at
300 K? (R = 8.314 J/mol·K)
a) 4986 J
b) 5742 J
c) 11484 J
d) 14958 J
Answer: c) 11484 J
51. The Clausius-Clapeyron equation relates:
a) Pressure and temperature for a phase change
b) Volume and temperature for a phase change
c) Entropy and temperature for a phase change
d) Enthalpy and pressure for a phase change
Answer: a) Pressure and temperature for a phase change
52. Which of the following is TRUE for an irreversible process?
a) ΔSuniverse > 0
b) ΔSuniverse < 0
c) ΔSuniverse = 0
d) ΔSuniverse can be positive or negative
Answer: a) ΔSuniverse > 0
53. What is the change in Gibbs free energy for a process at constant temperature and
pressure?
a) ΔG = ΔH + TΔS
b) ΔG = ΔH - TΔS
c) ΔG = ΔU + PΔV
d) ΔG = ΔU - TΔS
Answer: b) ΔG = ΔH - TΔS
54. The efficiency of a Carnot engine is independent of:
a) The working substance
b) The temperature of the hot reservoir
c) The temperature of the cold reservoir
d) The amount of heat absorbed
Answer: a) The working substance
55. Which of the following is TRUE for an ideal gas undergoing an isothermal process?
a) ΔU = 0
b) ΔH = 0
c) ΔS = 0
d) ΔG = 0
Answer: a) ΔU = 0
56. What is the change in entropy when 1 mole of an ideal gas is heated from 300 K to 600 K at
constant volume? (CV = 3R/2 for monatomic gas, R = 8.314 J/mol·K)
a) 8.664 J/K
b) 12.996 J/K
c) 17.328 J/K
d) 21.660 J/K
Answer: b) 12.996 J/K
57. Which of the following is NOT a characteristic of a heat engine?
a) It operates in a cycle
b) It converts heat entirely into work
c) It requires a temperature difference
d) It rejects some heat to a cold reservoir
Answer: b) It converts heat entirely into work
58. The Maxwell relations are derived from:
a) First law of thermodynamics
b) Second law of thermodynamics
c) Fundamental thermodynamic relations
d) Ideal gas law
Answer: c) Fundamental thermodynamic relations
59. What is the work done by an ideal gas expanding from 2 L to 5 L at a constant pressure of 2
atm?
a) 3 L·atm
b) 6 L·atm
c) -3 L·atm
d) -6 L·atm
Answer: d) -6 L·atm
60. Which of the following is TRUE for a process at constant temperature and volume?
a) ΔU = Q
b) ΔH = Q
c) ΔA = Q
d) ΔG = Q
Answer: c) ΔA = Q
61. The efficiency of a real heat engine is always:
a) Equal to the Carnot efficiency
b) Greater than the Carnot efficiency
c) Less than the Carnot efficiency
d) Independent of the Carnot efficiency
Answer: c) Less than the Carnot efficiency
62. What is the change in entropy when 100 g of ice at 0°C melts to water at 0°C? (Latent heat
of fusion of ice = 334 J/g)
a) 0.122 J/K
b) 1.22 J/K
c) 12.2 J/K
d) 122 J/K
Answer: c) 12.2 J/K
63. Which of the following is TRUE for an adiabatic process?
a) Q = 0
b) W = 0
c) ΔU = 0
d) ΔS = 0
Answer: a) Q = 0
64. The critical point of a substance is characterized by:
a) Highest possible temperature
b) Highest possible pressure
c) Coexistence of solid, liquid, and gas phases
d) Indistinguishability between liquid and gas phases
Answer: d) Indistinguishability between liquid and gas phases
65. What is the efficiency of a heat engine that absorbs 800 J of heat and produces 200 J of
work in each cycle?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
66. Which of the following is an intensive property?
a) Volume
b) Enthalpy
c) Entropy
d) Pressure
Answer: d) Pressure
67. The work done in an isothermal compression of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final pressures
Answer: b) Negative
68. What is the change in internal energy when 300 J of heat is added to a system and 150 J of
work is done by the system?
a) 150 J
b) 450 J
c) -150 J
d) -450 J
Answer: a) 150 J
69. Which of the following is TRUE for a reversible adiabatic process of an ideal gas?
a) PV = constant
b) TV^(γ-1) = constant
c) PT^(γ/(γ-1)) = constant
d) All of the above
Answer: d) All of the above
70. The entropy of mixing of two ideal gases is always:
a) Positive
b) Negative
c) Zero
d) Depends on the gases
Answer: a) Positive
71. What is the change in Helmholtz free energy for an isothermal process?
a) ΔA = ΔU
b) ΔA = -W
c) ΔA = Q
d) ΔA = ΔH
Answer: b) ΔA = -W
72. Which of the following is NOT a statement of the second law of thermodynamics?
a) Entropy of an isolated system always increases
b) Heat flows spontaneously from hot to cold
c) No process is 100% efficient
d) Energy is conserved in all processes
Answer: d) Energy is conserved in all processes
73. The coefficient of performance of a heat pump is always:
a) Less than 1
b) Equal to 1
c) Greater than 1
d) Equal to the efficiency of a Carnot engine
Answer: c) Greater than 1
74. What is the change in entropy when 2 moles of an ideal gas expands isothermally from 2 L
to 8 L at 400 K? (R = 8.314 J/mol·K)
a) 23.18 J/K
b) 46.36 J/K
c) 69.54 J/K
d) 92.72 J/K
Answer: b) 46.36 J/K
75. Which of the following is TRUE for a spontaneous process at constant T and P?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) ΔG has no relation to spontaneity
Answer: b) ΔG < 0
76. The internal energy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
77. What is the work done by 3 moles of an ideal gas expanding isothermally from 2 L to 6 L at
300 K? (R = 8.314 J/mol·K)
a) 4986 J
b) 5742 J
c) 8226 J
d) 9972 J
Answer: c) 8226 J
78. Which of the following is TRUE for an isentropic process?
a) ΔS = 0
b) ΔT = 0
c) ΔP = 0
d) ΔV = 0
Answer: a) ΔS = 0
79. The Joule-Thomson coefficient is zero for:
a) All ideal gases
b) Only monatomic ideal gases
c) Only diatomic ideal gases
d) No real gases
Answer: a) All ideal gases
80. What is the change in entropy when 200 g of water at 20°C is converted to steam at 100°C?
(Specific heat capacity of water = 4186 J/kg·K, Latent heat of vaporization of water = 2257 J/g)
a) 1046 J/K
b) 1256 J/K
c) 1466 J/K
d) 1676 J/K
Answer: c) 1466 J/K
81. Which of the following is an extensive property?
a) Temperature
b) Pressure
c) Density
d) Heat capacity
Answer: d) Heat capacity
82. The work done in an adiabatic expansion of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final temperatures
Answer: b) Negative
83. What is the efficiency of a heat engine operating between 400 K and 300 K?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
84. Which of the following is TRUE for a process at constant pressure?
a) ΔH = Q
b) ΔU = Q
c) ΔG = Q
d) ΔA = Q
Answer: a) ΔH = Q
85. The enthalpy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
86. What is the change in Gibbs free energy for a reversible process at constant temperature?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) Depends on the process
Answer: c) ΔG = 0
87. Which of the following is NOT a characteristic of an irreversible process?
a) Produces entropy
b) Can occur spontaneously
c) Can be reversed without leaving a trace
d) Results in less work than a reversible process
Answer: c) Can be reversed without leaving a trace
52. Which of the following is TRUE for an irreversible process?
a) ΔSuniverse > 0
b) ΔSuniverse < 0
c) ΔSuniverse = 0
d) ΔSuniverse can be positive or negative
Answer: a) ΔSuniverse > 0
53. What is the change in Gibbs free energy for a process at constant temperature and
pressure?
a) ΔG = ΔH + TΔS
b) ΔG = ΔH - TΔS
c) ΔG = ΔU + PΔV
d) ΔG = ΔU - TΔS
Answer: b) ΔG = ΔH - TΔS
54. The efficiency of a Carnot engine is independent of:
a) The working substance
b) The temperature of the hot reservoir
c) The temperature of the cold reservoir
d) The amount of heat absorbed
Answer: a) The working substance
55. Which of the following is TRUE for an ideal gas undergoing an isothermal process?
a) ΔU = 0
b) ΔH = 0
c) ΔS = 0
d) ΔG = 0
Answer: a) ΔU = 0
56. What is the change in entropy when 1 mole of an ideal gas is heated from 300 K to 600 K at
constant volume? (CV = 3R/2 for monatomic gas, R = 8.314 J/mol·K)
a) 8.664 J/K
b) 12.996 J/K
c) 17.328 J/K
d) 21.660 J/K
Answer: b) 12.996 J/K
57. Which of the following is NOT a characteristic of a heat engine?
a) It operates in a cycle
b) It converts heat entirely into work
c) It requires a temperature difference
d) It rejects some heat to a cold reservoir
Answer: b) It converts heat entirely into work
58. The Maxwell relations are derived from:
a) First law of thermodynamics
b) Second law of thermodynamics
c) Fundamental thermodynamic relations
d) Ideal gas law
Answer: c) Fundamental thermodynamic relations
59. What is the work done by an ideal gas expanding from 2 L to 5 L at a constant pressure of 2
atm?
a) 3 L·atm
b) 6 L·atm
c) -3 L·atm
d) -6 L·atm
Answer: d) -6 L·atm
60. Which of the following is TRUE for a process at constant temperature and volume?
a) ΔU = Q
b) ΔH = Q
c) ΔA = Q
d) ΔG = Q
Answer: c) ΔA = Q
61. The efficiency of a real heat engine is always:
a) Equal to the Carnot efficiency
b) Greater than the Carnot efficiency
c) Less than the Carnot efficiency
d) Independent of the Carnot efficiency
Answer: c) Less than the Carnot efficiency
62. What is the change in entropy when 100 g of ice at 0°C melts to water at 0°C? (Latent heat
of fusion of ice = 334 J/g)
a) 0.122 J/K
b) 1.22 J/K
c) 12.2 J/K
d) 122 J/K
Answer: c) 12.2 J/K
63. Which of the following is TRUE for an adiabatic process?
a) Q = 0
b) W = 0
c) ΔU = 0
d) ΔS = 0
Answer: a) Q = 0
64. The critical point of a substance is characterized by:
a) Highest possible temperature
b) Highest possible pressure
c) Coexistence of solid, liquid, and gas phases
d) Indistinguishability between liquid and gas phases
Answer: d) Indistinguishability between liquid and gas phases
65. What is the efficiency of a heat engine that absorbs 800 J of heat and produces 200 J of
work in each cycle?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
66. Which of the following is an intensive property?
a) Volume
b) Enthalpy
c) Entropy
d) Pressure
Answer: d) Pressure
67. The work done in an isothermal compression of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final pressures
Answer: b) Negative
68. What is the change in internal energy when 300 J of heat is added to a system and 150 J of
work is done by the system?
a) 150 J
b) 450 J
c) -150 J
d) -450 J
Answer: a) 150 J
69. Which of the following is TRUE for a reversible adiabatic process of an ideal gas?
a) PV = constant
b) TV^(γ-1) = constant
c) PT^(γ/(γ-1)) = constant
d) All of the above
Answer: d) All of the above
70. The entropy of mixing of two ideal gases is always:
a) Positive
b) Negative
c) Zero
d) Depends on the gases
Answer: a) Positive
71. What is the change in Helmholtz free energy for an isothermal process?
a) ΔA = ΔU
b) ΔA = -W
c) ΔA = Q
d) ΔA = ΔH
Answer: b) ΔA = -W
72. Which of the following is NOT a statement of the second law of thermodynamics?
a) Entropy of an isolated system always increases
b) Heat flows spontaneously from hot to cold
c) No process is 100% efficient
d) Energy is conserved in all processes
Answer: d) Energy is conserved in all processes
73. The coefficient of performance of a heat pump is always:
a) Less than 1
b) Equal to 1
c) Greater than 1
d) Equal to the efficiency of a Carnot engine
Answer: c) Greater than 1
74. What is the change in entropy when 2 moles of an ideal gas expands isothermally from 2 L
to 8 L at 400 K? (R = 8.314 J/mol·K)
a) 23.18 J/K
b) 46.36 J/K
c) 69.54 J/K
d) 92.72 J/K
Answer: b) 46.36 J/K
75. Which of the following is TRUE for a spontaneous process at constant T and P?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) ΔG has no relation to spontaneity
Answer: b) ΔG < 0
76. The internal energy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
77. What is the work done by 3 moles of an ideal gas expanding isothermally from 2 L to 6 L at
300 K? (R = 8.314 J/mol·K)
a) 4986 J
b) 5742 J
c) 8226 J
d) 9972 J
Answer: c) 8226 J
78. Which of the following is TRUE for an isentropic process?
a) ΔS = 0
b) ΔT = 0
c) ΔP = 0
d) ΔV = 0
Answer: a) ΔS = 0
79. The Joule-Thomson coefficient is zero for:
a) All ideal gases
b) Only monatomic ideal gases
c) Only diatomic ideal gases
d) No real gases
Answer: a) All ideal gases
80. What is the change in entropy when 200 g of water at 20°C is converted to steam at 100°C?
(Specific heat capacity of water = 4186 J/kg·K, Latent heat of vaporization of water = 2257 J/g)
a) 1046 J/K
b) 1256 J/K
c) 1466 J/K
d) 1676 J/K
Answer: c) 1466 J/K
81. Which of the following is an extensive property?
a) Temperature
b) Pressure
c) Density
d) Heat capacity
Answer: d) Heat capacity
82. The work done in an adiabatic expansion of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final temperatures
Answer: b) Negative
83. What is the efficiency of a heat engine operating between 400 K and 300 K?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
84. Which of the following is TRUE for a process at constant pressure?
a) ΔH = Q
b) ΔU = Q
c) ΔG = Q
d) ΔA = Q
Answer: a) ΔH = Q
85. The enthalpy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
86. What is the change in Gibbs free energy for a reversible process at constant temperature?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) Depends on the process
Answer: c) ΔG = 0
87. Which of the following is NOT a characteristic of an irreversible process?
a) Produces entropy
b) Can occur spontaneously
c) Can be reversed without leaving a trace
d) Results in less work than a reversible process
Answer: c) Can be reversed without leaving a trace
52. Which of the following is TRUE for an irreversible process?
a) ΔSuniverse > 0
b) ΔSuniverse < 0
c) ΔSuniverse = 0
d) ΔSuniverse can be positive or negative
Answer: a) ΔSuniverse > 0
53. What is the change in Gibbs free energy for a process at constant temperature and
pressure?
a) ΔG = ΔH + TΔS
b) ΔG = ΔH - TΔS
c) ΔG = ΔU + PΔV
d) ΔG = ΔU - TΔS
Answer: b) ΔG = ΔH - TΔS
54. The efficiency of a Carnot engine is independent of:
a) The working substance
b) The temperature of the hot reservoir
c) The temperature of the cold reservoir
d) The amount of heat absorbed
Answer: a) The working substance
55. Which of the following is TRUE for an ideal gas undergoing an isothermal process?
a) ΔU = 0
b) ΔH = 0
c) ΔS = 0
d) ΔG = 0
Answer: a) ΔU = 0
56. What is the change in entropy when 1 mole of an ideal gas is heated from 300 K to 600 K at
constant volume? (CV = 3R/2 for monatomic gas, R = 8.314 J/mol·K)
a) 8.664 J/K
b) 12.996 J/K
c) 17.328 J/K
d) 21.660 J/K
Answer: b) 12.996 J/K
57. Which of the following is NOT a characteristic of a heat engine?
a) It operates in a cycle
b) It converts heat entirely into work
c) It requires a temperature difference
d) It rejects some heat to a cold reservoir
Answer: b) It converts heat entirely into work
58. The Maxwell relations are derived from:
a) First law of thermodynamics
b) Second law of thermodynamics
c) Fundamental thermodynamic relations
d) Ideal gas law
Answer: c) Fundamental thermodynamic relations
59. What is the work done by an ideal gas expanding from 2 L to 5 L at a constant pressure of 2
atm?
a) 3 L·atm
b) 6 L·atm
c) -3 L·atm
d) -6 L·atm
Answer: d) -6 L·atm
60. Which of the following is TRUE for a process at constant temperature and volume?
a) ΔU = Q
b) ΔH = Q
c) ΔA = Q
d) ΔG = Q
Answer: c) ΔA = Q
61. The efficiency of a real heat engine is always:
a) Equal to the Carnot efficiency
b) Greater than the Carnot efficiency
c) Less than the Carnot efficiency
d) Independent of the Carnot efficiency
Answer: c) Less than the Carnot efficiency
62. What is the change in entropy when 100 g of ice at 0°C melts to water at 0°C? (Latent heat
of fusion of ice = 334 J/g)
a) 0.122 J/K
b) 1.22 J/K
c) 12.2 J/K
d) 122 J/K
Answer: c) 12.2 J/K
63. Which of the following is TRUE for an adiabatic process?
a) Q = 0
b) W = 0
c) ΔU = 0
d) ΔS = 0
Answer: a) Q = 0
64. The critical point of a substance is characterized by:
a) Highest possible temperature
b) Highest possible pressure
c) Coexistence of solid, liquid, and gas phases
d) Indistinguishability between liquid and gas phases
Answer: d) Indistinguishability between liquid and gas phases
65. What is the efficiency of a heat engine that absorbs 800 J of heat and produces 200 J of
work in each cycle?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
66. Which of the following is an intensive property?
a) Volume
b) Enthalpy
c) Entropy
d) Pressure
Answer: d) Pressure
67. The work done in an isothermal compression of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final pressures
Answer: b) Negative
68. What is the change in internal energy when 300 J of heat is added to a system and 150 J of
work is done by the system?
a) 150 J
b) 450 J
c) -150 J
d) -450 J
Answer: a) 150 J
69. Which of the following is TRUE for a reversible adiabatic process of an ideal gas?
a) PV = constant
b) TV^(γ-1) = constant
c) PT^(γ/(γ-1)) = constant
d) All of the above
Answer: d) All of the above
70. The entropy of mixing of two ideal gases is always:
a) Positive
b) Negative
c) Zero
d) Depends on the gases
Answer: a) Positive
71. What is the change in Helmholtz free energy for an isothermal process?
a) ΔA = ΔU
b) ΔA = -W
c) ΔA = Q
d) ΔA = ΔH
Answer: b) ΔA = -W
72. Which of the following is NOT a statement of the second law of thermodynamics?
a) Entropy of an isolated system always increases
b) Heat flows spontaneously from hot to cold
c) No process is 100% efficient
d) Energy is conserved in all processes
Answer: d) Energy is conserved in all processes
73. The coefficient of performance of a heat pump is always:
a) Less than 1
b) Equal to 1
c) Greater than 1
d) Equal to the efficiency of a Carnot engine
Answer: c) Greater than 1
74. What is the change in entropy when 2 moles of an ideal gas expands isothermally from 2 L
to 8 L at 400 K? (R = 8.314 J/mol·K)
a) 23.18 J/K
b) 46.36 J/K
c) 69.54 J/K
d) 92.72 J/K
Answer: b) 46.36 J/K
75. Which of the following is TRUE for a spontaneous process at constant T and P?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) ΔG has no relation to spontaneity
Answer: b) ΔG < 0
76. The internal energy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
77. What is the work done by 3 moles of an ideal gas expanding isothermally from 2 L to 6 L at
300 K? (R = 8.314 J/mol·K)
a) 4986 J
b) 5742 J
c) 8226 J
d) 9972 J
Answer: c) 8226 J
78. Which of the following is TRUE for an isentropic process?
a) ΔS = 0
b) ΔT = 0
c) ΔP = 0
d) ΔV = 0
Answer: a) ΔS = 0
79. The Joule-Thomson coefficient is zero for:
a) All ideal gases
b) Only monatomic ideal gases
c) Only diatomic ideal gases
d) No real gases
Answer: a) All ideal gases
80. What is the change in entropy when 200 g of water at 20°C is converted to steam at 100°C?
(Specific heat capacity of water = 4186 J/kg·K, Latent heat of vaporization of water = 2257 J/g)
a) 1046 J/K
b) 1256 J/K
c) 1466 J/K
d) 1676 J/K
Answer: c) 1466 J/K
81. Which of the following is an extensive property?
a) Temperature
b) Pressure
c) Density
d) Heat capacity
Answer: d) Heat capacity
82. The work done in an adiabatic expansion of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final temperatures
Answer: b) Negative
83. What is the efficiency of a heat engine operating between 400 K and 300 K?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
84. Which of the following is TRUE for a process at constant pressure?
a) ΔH = Q
b) ΔU = Q
c) ΔG = Q
d) ΔA = Q
Answer: a) ΔH = Q
85. The enthalpy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
86. What is the change in Gibbs free energy for a reversible process at constant temperature?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) Depends on the process
Answer: c) ΔG = 0
87. Which of the following is NOT a characteristic of an irreversible process?
a) Produces entropy
b) Can occur spontaneously
c) Can be reversed without leaving a trace
d) Results in less work than a reversible process
Answer: c) Can be reversed without leaving a trace
52. Which of the following is TRUE for an irreversible process?
a) ΔSuniverse > 0
b) ΔSuniverse < 0
c) ΔSuniverse = 0
d) ΔSuniverse can be positive or negative
Answer: a) ΔSuniverse > 0
53. What is the change in Gibbs free energy for a process at constant temperature and
pressure?
a) ΔG = ΔH + TΔS
b) ΔG = ΔH - TΔS
c) ΔG = ΔU + PΔV
d) ΔG = ΔU - TΔS
Answer: b) ΔG = ΔH - TΔS
54. The efficiency of a Carnot engine is independent of:
a) The working substance
b) The temperature of the hot reservoir
c) The temperature of the cold reservoir
d) The amount of heat absorbed
Answer: a) The working substance
55. Which of the following is TRUE for an ideal gas undergoing an isothermal process?
a) ΔU = 0
b) ΔH = 0
c) ΔS = 0
d) ΔG = 0
Answer: a) ΔU = 0
56. What is the change in entropy when 1 mole of an ideal gas is heated from 300 K to 600 K at
constant volume? (CV = 3R/2 for monatomic gas, R = 8.314 J/mol·K)
a) 8.664 J/K
b) 12.996 J/K
c) 17.328 J/K
d) 21.660 J/K
Answer: b) 12.996 J/K
57. Which of the following is NOT a characteristic of a heat engine?
a) It operates in a cycle
b) It converts heat entirely into work
c) It requires a temperature difference
d) It rejects some heat to a cold reservoir
Answer: b) It converts heat entirely into work
58. The Maxwell relations are derived from:
a) First law of thermodynamics
b) Second law of thermodynamics
c) Fundamental thermodynamic relations
d) Ideal gas law
Answer: c) Fundamental thermodynamic relations
59. What is the work done by an ideal gas expanding from 2 L to 5 L at a constant pressure of 2
atm?
a) 3 L·atm
b) 6 L·atm
c) -3 L·atm
d) -6 L·atm
Answer: d) -6 L·atm
60. Which of the following is TRUE for a process at constant temperature and volume?
a) ΔU = Q
b) ΔH = Q
c) ΔA = Q
d) ΔG = Q
Answer: c) ΔA = Q
61. The efficiency of a real heat engine is always:
a) Equal to the Carnot efficiency
b) Greater than the Carnot efficiency
c) Less than the Carnot efficiency
d) Independent of the Carnot efficiency
Answer: c) Less than the Carnot efficiency
62. What is the change in entropy when 100 g of ice at 0°C melts to water at 0°C? (Latent heat
of fusion of ice = 334 J/g)
a) 0.122 J/K
b) 1.22 J/K
c) 12.2 J/K
d) 122 J/K
Answer: c) 12.2 J/K
63. Which of the following is TRUE for an adiabatic process?
a) Q = 0
b) W = 0
c) ΔU = 0
d) ΔS = 0
Answer: a) Q = 0
64. The critical point of a substance is characterized by:
a) Highest possible temperature
b) Highest possible pressure
c) Coexistence of solid, liquid, and gas phases
d) Indistinguishability between liquid and gas phases
Answer: d) Indistinguishability between liquid and gas phases
65. What is the efficiency of a heat engine that absorbs 800 J of heat and produces 200 J of
work in each cycle?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
66. Which of the following is an intensive property?
a) Volume
b) Enthalpy
c) Entropy
d) Pressure
Answer: d) Pressure
67. The work done in an isothermal compression of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final pressures
Answer: b) Negative
68. What is the change in internal energy when 300 J of heat is added to a system and 150 J of
work is done by the system?
a) 150 J
b) 450 J
c) -150 J
d) -450 J
Answer: a) 150 J
69. Which of the following is TRUE for a reversible adiabatic process of an ideal gas?
a) PV = constant
b) TV^(γ-1) = constant
c) PT^(γ/(γ-1)) = constant
d) All of the above
Answer: d) All of the above
70. The entropy of mixing of two ideal gases is always:
a) Positive
b) Negative
c) Zero
d) Depends on the gases
Answer: a) Positive
71. What is the change in Helmholtz free energy for an isothermal process?
a) ΔA = ΔU
b) ΔA = -W
c) ΔA = Q
d) ΔA = ΔH
Answer: b) ΔA = -W
72. Which of the following is NOT a statement of the second law of thermodynamics?
a) Entropy of an isolated system always increases
b) Heat flows spontaneously from hot to cold
c) No process is 100% efficient
d) Energy is conserved in all processes
Answer: d) Energy is conserved in all processes
73. The coefficient of performance of a heat pump is always:
a) Less than 1
b) Equal to 1
c) Greater than 1
d) Equal to the efficiency of a Carnot engine
Answer: c) Greater than 1
74. What is the change in entropy when 2 moles of an ideal gas expands isothermally from 2 L
to 8 L at 400 K? (R = 8.314 J/mol·K)
a) 23.18 J/K
b) 46.36 J/K
c) 69.54 J/K
d) 92.72 J/K
Answer: b) 46.36 J/K
75. Which of the following is TRUE for a spontaneous process at constant T and P?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) ΔG has no relation to spontaneity
Answer: b) ΔG < 0
76. The internal energy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
77. What is the work done by 3 moles of an ideal gas expanding isothermally from 2 L to 6 L at
300 K? (R = 8.314 J/mol·K)
a) 4986 J
b) 5742 J
c) 8226 J
d) 9972 J
Answer: c) 8226 J
78. Which of the following is TRUE for an isentropic process?
a) ΔS = 0
b) ΔT = 0
c) ΔP = 0
d) ΔV = 0
Answer: a) ΔS = 0
79. The Joule-Thomson coefficient is zero for:
a) All ideal gases
b) Only monatomic ideal gases
c) Only diatomic ideal gases
d) No real gases
Answer: a) All ideal gases
80. What is the change in entropy when 200 g of water at 20°C is converted to steam at 100°C?
(Specific heat capacity of water = 4186 J/kg·K, Latent heat of vaporization of water = 2257 J/g)
a) 1046 J/K
b) 1256 J/K
c) 1466 J/K
d) 1676 J/K
Answer: c) 1466 J/K
81. Which of the following is an extensive property?
a) Temperature
b) Pressure
c) Density
d) Heat capacity
Answer: d) Heat capacity
82. The work done in an adiabatic expansion of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final temperatures
Answer: b) Negative
83. What is the efficiency of a heat engine operating between 400 K and 300 K?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
84. Which of the following is TRUE for a process at constant pressure?
a) ΔH = Q
b) ΔU = Q
c) ΔG = Q
d) ΔA = Q
Answer: a) ΔH = Q
85. The enthalpy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
86. What is the change in Gibbs free energy for a reversible process at constant temperature?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) Depends on the process
Answer: c) ΔG = 0
87. Which of the following is NOT a characteristic of an irreversible process?
a) Produces entropy
b) Can occur spontaneously
c) Can be reversed without leaving a trace
d) Results in less work than a reversible process
Answer: c) Can be reversed without leaving a trace
52. Which of the following is TRUE for an irreversible process?
a) ΔSuniverse > 0
b) ΔSuniverse < 0
c) ΔSuniverse = 0
d) ΔSuniverse can be positive or negative
Answer: a) ΔSuniverse > 0
53. What is the change in Gibbs free energy for a process at constant temperature and
pressure?
a) ΔG = ΔH + TΔS
b) ΔG = ΔH - TΔS
c) ΔG = ΔU + PΔV
d) ΔG = ΔU - TΔS
Answer: b) ΔG = ΔH - TΔS
54. The efficiency of a Carnot engine is independent of:
a) The working substance
b) The temperature of the hot reservoir
c) The temperature of the cold reservoir
d) The amount of heat absorbed
Answer: a) The working substance
55. Which of the following is TRUE for an ideal gas undergoing an isothermal process?
a) ΔU = 0
b) ΔH = 0
c) ΔS = 0
d) ΔG = 0
Answer: a) ΔU = 0
56. What is the change in entropy when 1 mole of an ideal gas is heated from 300 K to 600 K at
constant volume? (CV = 3R/2 for monatomic gas, R = 8.314 J/mol·K)
a) 8.664 J/K
b) 12.996 J/K
c) 17.328 J/K
d) 21.660 J/K
Answer: b) 12.996 J/K
57. Which of the following is NOT a characteristic of a heat engine?
a) It operates in a cycle
b) It converts heat entirely into work
c) It requires a temperature difference
d) It rejects some heat to a cold reservoir
Answer: b) It converts heat entirely into work
58. The Maxwell relations are derived from:
a) First law of thermodynamics
b) Second law of thermodynamics
c) Fundamental thermodynamic relations
d) Ideal gas law
Answer: c) Fundamental thermodynamic relations
59. What is the work done by an ideal gas expanding from 2 L to 5 L at a constant pressure of 2
atm?
a) 3 L·atm
b) 6 L·atm
c) -3 L·atm
d) -6 L·atm
Answer: d) -6 L·atm
60. Which of the following is TRUE for a process at constant temperature and volume?
a) ΔU = Q
b) ΔH = Q
c) ΔA = Q
d) ΔG = Q
Answer: c) ΔA = Q
61. The efficiency of a real heat engine is always:
a) Equal to the Carnot efficiency
b) Greater than the Carnot efficiency
c) Less than the Carnot efficiency
d) Independent of the Carnot efficiency
Answer: c) Less than the Carnot efficiency
62. What is the change in entropy when 100 g of ice at 0°C melts to water at 0°C? (Latent heat
of fusion of ice = 334 J/g)
a) 0.122 J/K
b) 1.22 J/K
c) 12.2 J/K
d) 122 J/K
Answer: c) 12.2 J/K
63. Which of the following is TRUE for an adiabatic process?
a) Q = 0
b) W = 0
c) ΔU = 0
d) ΔS = 0
Answer: a) Q = 0
64. The critical point of a substance is characterized by:
a) Highest possible temperature
b) Highest possible pressure
c) Coexistence of solid, liquid, and gas phases
d) Indistinguishability between liquid and gas phases
Answer: d) Indistinguishability between liquid and gas phases
65. What is the efficiency of a heat engine that absorbs 800 J of heat and produces 200 J of
work in each cycle?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
66. Which of the following is an intensive property?
a) Volume
b) Enthalpy
c) Entropy
d) Pressure
Answer: d) Pressure
67. The work done in an isothermal compression of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final pressures
Answer: b) Negative
68. What is the change in internal energy when 300 J of heat is added to a system and 150 J of
work is done by the system?
a) 150 J
b) 450 J
c) -150 J
d) -450 J
Answer: a) 150 J
69. Which of the following is TRUE for a reversible adiabatic process of an ideal gas?
a) PV = constant
b) TV^(γ-1) = constant
c) PT^(γ/(γ-1)) = constant
d) All of the above
Answer: d) All of the above
70. The entropy of mixing of two ideal gases is always:
a) Positive
b) Negative
c) Zero
d) Depends on the gases
Answer: a) Positive
71. What is the change in Helmholtz free energy for an isothermal process?
a) ΔA = ΔU
b) ΔA = -W
c) ΔA = Q
d) ΔA = ΔH
Answer: b) ΔA = -W
72. Which of the following is NOT a statement of the second law of thermodynamics?
a) Entropy of an isolated system always increases
b) Heat flows spontaneously from hot to cold
c) No process is 100% efficient
d) Energy is conserved in all processes
Answer: d) Energy is conserved in all processes
73. The coefficient of performance of a heat pump is always:
a) Less than 1
b) Equal to 1
c) Greater than 1
d) Equal to the efficiency of a Carnot engine
Answer: c) Greater than 1
74. What is the change in entropy when 2 moles of an ideal gas expands isothermally from 2 L
to 8 L at 400 K? (R = 8.314 J/mol·K)
a) 23.18 J/K
b) 46.36 J/K
c) 69.54 J/K
d) 92.72 J/K
Answer: b) 46.36 J/K
75. Which of the following is TRUE for a spontaneous process at constant T and P?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) ΔG has no relation to spontaneity
Answer: b) ΔG < 0
76. The internal energy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
77. What is the work done by 3 moles of an ideal gas expanding isothermally from 2 L to 6 L at
300 K? (R = 8.314 J/mol·K)
a) 4986 J
b) 5742 J
c) 8226 J
d) 9972 J
Answer: c) 8226 J
78. Which of the following is TRUE for an isentropic process?
a) ΔS = 0
b) ΔT = 0
c) ΔP = 0
d) ΔV = 0
Answer: a) ΔS = 0
79. The Joule-Thomson coefficient is zero for:
a) All ideal gases
b) Only monatomic ideal gases
c) Only diatomic ideal gases
d) No real gases
Answer: a) All ideal gases
80. What is the change in entropy when 200 g of water at 20°C is converted to steam at 100°C?
(Specific heat capacity of water = 4186 J/kg·K, Latent heat of vaporization of water = 2257 J/g)
a) 1046 J/K
b) 1256 J/K
c) 1466 J/K
d) 1676 J/K
Answer: c) 1466 J/K
81. Which of the following is an extensive property?
a) Temperature
b) Pressure
c) Density
d) Heat capacity
Answer: d) Heat capacity
82. The work done in an adiabatic expansion of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final temperatures
Answer: b) Negative
83. What is the efficiency of a heat engine operating between 400 K and 300 K?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
84. Which of the following is TRUE for a process at constant pressure?
a) ΔH = Q
b) ΔU = Q
c) ΔG = Q
d) ΔA = Q
Answer: a) ΔH = Q
85. The enthalpy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
86. What is the change in Gibbs free energy for a reversible process at constant temperature?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) Depends on the process
Answer: c) ΔG = 0
87. Which of the following is NOT a characteristic of an irreversible process?
a) Produces entropy
b) Can occur spontaneously
c) Can be reversed without leaving a trace
d) Results in less work than a reversible process
Answer: c) Can be reversed without leaving a trace
52. Which of the following is TRUE for an irreversible process?
a) ΔSuniverse > 0
b) ΔSuniverse < 0
c) ΔSuniverse = 0
d) ΔSuniverse can be positive or negative
Answer: a) ΔSuniverse > 0
53. What is the change in Gibbs free energy for a process at constant temperature and
pressure?
a) ΔG = ΔH + TΔS
b) ΔG = ΔH - TΔS
c) ΔG = ΔU + PΔV
d) ΔG = ΔU - TΔS
Answer: b) ΔG = ΔH - TΔS
54. The efficiency of a Carnot engine is independent of:
a) The working substance
b) The temperature of the hot reservoir
c) The temperature of the cold reservoir
d) The amount of heat absorbed
Answer: a) The working substance
55. Which of the following is TRUE for an ideal gas undergoing an isothermal process?
a) ΔU = 0
b) ΔH = 0
c) ΔS = 0
d) ΔG = 0
Answer: a) ΔU = 0
56. What is the change in entropy when 1 mole of an ideal gas is heated from 300 K to 600 K at
constant volume? (CV = 3R/2 for monatomic gas, R = 8.314 J/mol·K)
a) 8.664 J/K
b) 12.996 J/K
c) 17.328 J/K
d) 21.660 J/K
Answer: b) 12.996 J/K
57. Which of the following is NOT a characteristic of a heat engine?
a) It operates in a cycle
b) It converts heat entirely into work
c) It requires a temperature difference
d) It rejects some heat to a cold reservoir
Answer: b) It converts heat entirely into work
58. The Maxwell relations are derived from:
a) First law of thermodynamics
b) Second law of thermodynamics
c) Fundamental thermodynamic relations
d) Ideal gas law
Answer: c) Fundamental thermodynamic relations
59. What is the work done by an ideal gas expanding from 2 L to 5 L at a constant pressure of 2
atm?
a) 3 L·atm
b) 6 L·atm
c) -3 L·atm
d) -6 L·atm
Answer: d) -6 L·atm
60. Which of the following is TRUE for a process at constant temperature and volume?
a) ΔU = Q
b) ΔH = Q
c) ΔA = Q
d) ΔG = Q
Answer: c) ΔA = Q
61. The efficiency of a real heat engine is always:
a) Equal to the Carnot efficiency
b) Greater than the Carnot efficiency
c) Less than the Carnot efficiency
d) Independent of the Carnot efficiency
Answer: c) Less than the Carnot efficiency
62. What is the change in entropy when 100 g of ice at 0°C melts to water at 0°C? (Latent heat
of fusion of ice = 334 J/g)
a) 0.122 J/K
b) 1.22 J/K
c) 12.2 J/K
d) 122 J/K
Answer: c) 12.2 J/K
63. Which of the following is TRUE for an adiabatic process?
a) Q = 0
b) W = 0
c) ΔU = 0
d) ΔS = 0
Answer: a) Q = 0
64. The critical point of a substance is characterized by:
a) Highest possible temperature
b) Highest possible pressure
c) Coexistence of solid, liquid, and gas phases
d) Indistinguishability between liquid and gas phases
Answer: d) Indistinguishability between liquid and gas phases
65. What is the efficiency of a heat engine that absorbs 800 J of heat and produces 200 J of
work in each cycle?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
66. Which of the following is an intensive property?
a) Volume
b) Enthalpy
c) Entropy
d) Pressure
Answer: d) Pressure
67. The work done in an isothermal compression of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final pressures
Answer: b) Negative
68. What is the change in internal energy when 300 J of heat is added to a system and 150 J of
work is done by the system?
a) 150 J
b) 450 J
c) -150 J
d) -450 J
Answer: a) 150 J
69. Which of the following is TRUE for a reversible adiabatic process of an ideal gas?
a) PV = constant
b) TV^(γ-1) = constant
c) PT^(γ/(γ-1)) = constant
d) All of the above
Answer: d) All of the above
70. The entropy of mixing of two ideal gases is always:
a) Positive
b) Negative
c) Zero
d) Depends on the gases
Answer: a) Positive
71. What is the change in Helmholtz free energy for an isothermal process?
a) ΔA = ΔU
b) ΔA = -W
c) ΔA = Q
d) ΔA = ΔH
Answer: b) ΔA = -W
72. Which of the following is NOT a statement of the second law of thermodynamics?
a) Entropy of an isolated system always increases
b) Heat flows spontaneously from hot to cold
c) No process is 100% efficient
d) Energy is conserved in all processes
Answer: d) Energy is conserved in all processes
73. The coefficient of performance of a heat pump is always:
a) Less than 1
b) Equal to 1
c) Greater than 1
d) Equal to the efficiency of a Carnot engine
Answer: c) Greater than 1
74. What is the change in entropy when 2 moles of an ideal gas expands isothermally from 2 L
to 8 L at 400 K? (R = 8.314 J/mol·K)
a) 23.18 J/K
b) 46.36 J/K
c) 69.54 J/K
d) 92.72 J/K
Answer: b) 46.36 J/K
75. Which of the following is TRUE for a spontaneous process at constant T and P?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) ΔG has no relation to spontaneity
Answer: b) ΔG < 0
76. The internal energy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
77. What is the work done by 3 moles of an ideal gas expanding isothermally from 2 L to 6 L at
300 K? (R = 8.314 J/mol·K)
a) 4986 J
b) 5742 J
c) 8226 J
d) 9972 J
Answer: c) 8226 J
78. Which of the following is TRUE for an isentropic process?
a) ΔS = 0
b) ΔT = 0
c) ΔP = 0
d) ΔV = 0
Answer: a) ΔS = 0
79. The Joule-Thomson coefficient is zero for:
a) All ideal gases
b) Only monatomic ideal gases
c) Only diatomic ideal gases
d) No real gases
Answer: a) All ideal gases
80. What is the change in entropy when 200 g of water at 20°C is converted to steam at 100°C?
(Specific heat capacity of water = 4186 J/kg·K, Latent heat of vaporization of water = 2257 J/g)
a) 1046 J/K
b) 1256 J/K
c) 1466 J/K
d) 1676 J/K
Answer: c) 1466 J/K
81. Which of the following is an extensive property?
a) Temperature
b) Pressure
c) Density
d) Heat capacity
Answer: d) Heat capacity
82. The work done in an adiabatic expansion of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final temperatures
Answer: b) Negative
83. What is the efficiency of a heat engine operating between 400 K and 300 K?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
84. Which of the following is TRUE for a process at constant pressure?
a) ΔH = Q
b) ΔU = Q
c) ΔG = Q
d) ΔA = Q
Answer: a) ΔH = Q
85. The enthalpy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
86. What is the change in Gibbs free energy for a reversible process at constant temperature?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) Depends on the process
Answer: c) ΔG = 0
87. Which of the following is NOT a characteristic of an irreversible process?
a) Produces entropy
b) Can occur spontaneously
c) Can be reversed without leaving a trace
d) Results in less work than a reversible process
Answer: c) Can be reversed without leaving a trace
52. Which of the following is TRUE for an irreversible process?
a) ΔSuniverse > 0
b) ΔSuniverse < 0
c) ΔSuniverse = 0
d) ΔSuniverse can be positive or negative
Answer: a) ΔSuniverse > 0
53. What is the change in Gibbs free energy for a process at constant temperature and
pressure?
a) ΔG = ΔH + TΔS
b) ΔG = ΔH - TΔS
c) ΔG = ΔU + PΔV
d) ΔG = ΔU - TΔS
Answer: b) ΔG = ΔH - TΔS
54. The efficiency of a Carnot engine is independent of:
a) The working substance
b) The temperature of the hot reservoir
c) The temperature of the cold reservoir
d) The amount of heat absorbed
Answer: a) The working substance
55. Which of the following is TRUE for an ideal gas undergoing an isothermal process?
a) ΔU = 0
b) ΔH = 0
c) ΔS = 0
d) ΔG = 0
Answer: a) ΔU = 0
56. What is the change in entropy when 1 mole of an ideal gas is heated from 300 K to 600 K at
constant volume? (CV = 3R/2 for monatomic gas, R = 8.314 J/mol·K)
a) 8.664 J/K
b) 12.996 J/K
c) 17.328 J/K
d) 21.660 J/K
Answer: b) 12.996 J/K
57. Which of the following is NOT a characteristic of a heat engine?
a) It operates in a cycle
b) It converts heat entirely into work
c) It requires a temperature difference
d) It rejects some heat to a cold reservoir
Answer: b) It converts heat entirely into work
58. The Maxwell relations are derived from:
a) First law of thermodynamics
b) Second law of thermodynamics
c) Fundamental thermodynamic relations
d) Ideal gas law
Answer: c) Fundamental thermodynamic relations
59. What is the work done by an ideal gas expanding from 2 L to 5 L at a constant pressure of 2
atm?
a) 3 L·atm
b) 6 L·atm
c) -3 L·atm
d) -6 L·atm
Answer: d) -6 L·atm
60. Which of the following is TRUE for a process at constant temperature and volume?
a) ΔU = Q
b) ΔH = Q
c) ΔA = Q
d) ΔG = Q
Answer: c) ΔA = Q
61. The efficiency of a real heat engine is always:
a) Equal to the Carnot efficiency
b) Greater than the Carnot efficiency
c) Less than the Carnot efficiency
d) Independent of the Carnot efficiency
Answer: c) Less than the Carnot efficiency
62. What is the change in entropy when 100 g of ice at 0°C melts to water at 0°C? (Latent heat
of fusion of ice = 334 J/g)
a) 0.122 J/K
b) 1.22 J/K
c) 12.2 J/K
d) 122 J/K
Answer: c) 12.2 J/K
63. Which of the following is TRUE for an adiabatic process?
a) Q = 0
b) W = 0
c) ΔU = 0
d) ΔS = 0
Answer: a) Q = 0
64. The critical point of a substance is characterized by:
a) Highest possible temperature
b) Highest possible pressure
c) Coexistence of solid, liquid, and gas phases
d) Indistinguishability between liquid and gas phases
Answer: d) Indistinguishability between liquid and gas phases
65. What is the efficiency of a heat engine that absorbs 800 J of heat and produces 200 J of
work in each cycle?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
66. Which of the following is an intensive property?
a) Volume
b) Enthalpy
c) Entropy
d) Pressure
Answer: d) Pressure
67. The work done in an isothermal compression of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final pressures
Answer: b) Negative
68. What is the change in internal energy when 300 J of heat is added to a system and 150 J of
work is done by the system?
a) 150 J
b) 450 J
c) -150 J
d) -450 J
Answer: a) 150 J
69. Which of the following is TRUE for a reversible adiabatic process of an ideal gas?
a) PV = constant
b) TV^(γ-1) = constant
c) PT^(γ/(γ-1)) = constant
d) All of the above
Answer: d) All of the above
70. The entropy of mixing of two ideal gases is always:
a) Positive
b) Negative
c) Zero
d) Depends on the gases
Answer: a) Positive
71. What is the change in Helmholtz free energy for an isothermal process?
a) ΔA = ΔU
b) ΔA = -W
c) ΔA = Q
d) ΔA = ΔH
Answer: b) ΔA = -W
72. Which of the following is NOT a statement of the second law of thermodynamics?
a) Entropy of an isolated system always increases
b) Heat flows spontaneously from hot to cold
c) No process is 100% efficient
d) Energy is conserved in all processes
Answer: d) Energy is conserved in all processes
73. The coefficient of performance of a heat pump is always:
a) Less than 1
b) Equal to 1
c) Greater than 1
d) Equal to the efficiency of a Carnot engine
Answer: c) Greater than 1
74. What is the change in entropy when 2 moles of an ideal gas expands isothermally from 2 L
to 8 L at 400 K? (R = 8.314 J/mol·K)
a) 23.18 J/K
b) 46.36 J/K
c) 69.54 J/K
d) 92.72 J/K
Answer: b) 46.36 J/K
75. Which of the following is TRUE for a spontaneous process at constant T and P?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) ΔG has no relation to spontaneity
Answer: b) ΔG < 0
76. The internal energy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
77. What is the work done by 3 moles of an ideal gas expanding isothermally from 2 L to 6 L at
300 K? (R = 8.314 J/mol·K)
a) 4986 J
b) 5742 J
c) 8226 J
d) 9972 J
Answer: c) 8226 J
78. Which of the following is TRUE for an isentropic process?
a) ΔS = 0
b) ΔT = 0
c) ΔP = 0
d) ΔV = 0
Answer: a) ΔS = 0
79. The Joule-Thomson coefficient is zero for:
a) All ideal gases
b) Only monatomic ideal gases
c) Only diatomic ideal gases
d) No real gases
Answer: a) All ideal gases
80. What is the change in entropy when 200 g of water at 20°C is converted to steam at 100°C?
(Specific heat capacity of water = 4186 J/kg·K, Latent heat of vaporization of water = 2257 J/g)
a) 1046 J/K
b) 1256 J/K
c) 1466 J/K
d) 1676 J/K
Answer: c) 1466 J/K
81. Which of the following is an extensive property?
a) Temperature
b) Pressure
c) Density
d) Heat capacity
Answer: d) Heat capacity
82. The work done in an adiabatic expansion of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final temperatures
Answer: b) Negative
83. What is the efficiency of a heat engine operating between 400 K and 300 K?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
84. Which of the following is TRUE for a process at constant pressure?
a) ΔH = Q
b) ΔU = Q
c) ΔG = Q
d) ΔA = Q
Answer: a) ΔH = Q
85. The enthalpy of an ideal gas depends on:
a) Pressure only
b) Volume only
c) Temperature only
d) Both pressure and volume
Answer: c) Temperature only
86. What is the change in Gibbs free energy for a reversible process at constant temperature?
a) ΔG > 0
b) ΔG < 0
c) ΔG = 0
d) Depends on the process
Answer: c) ΔG = 0
87. Which of the following is NOT a characteristic of an irreversible process?
a) Produces entropy
b) Can occur spontaneously
c) Can be reversed without leaving a trace
d) Results in less work than a reversible process
Answer: c) Can be reversed without leaving a trace
88. The heat capacity at constant pressure (CP) is always:
a) Equal to CV
b) Less than CV
c) Greater than CV
d) Not related to CV
Answer: c) Greater than CV
89. What is the work done when 2 moles of an ideal gas is compressed isothermally from 10 L
to 2 L at 300 K? (R = 8.314 J/mol·K)
a) 6932 J
b) -6932 J
c) 8664 J
d) -8664 J
Answer: b) -6932 J
90. Which of the following is TRUE for a process at constant volume?
a) W = 0
b) Q = 0
c) ΔU = 0
d) ΔH = 0
Answer: a) W = 0
91. The entropy of the universe:
a) Always increases
b) Always decreases
c) Remains constant
d) Can increase or decrease
Answer: a) Always increases
92. What is the change in internal energy when 400 J of heat is added to a system and 150 J of
work is done on the system?
a) 250 J
b) 550 J
c) -250 J
d) -550 J
Answer: b) 550 J
93. Which of the following is TRUE for an ideal gas undergoing an adiabatic process?
a) ΔT = 0
b) ΔP = 0
c) ΔV = 0
d) ΔS = 0
Answer: d) ΔS = 0
94. The Carnot cycle consists of:
a) Two isothermal and two adiabatic processes
b) Two isobaric and two isochoric processes
c) Four isothermal processes
d) Four adiabatic processes
Answer: a) Two isothermal and two adiabatic processes
95. What is the change in entropy when 1 kg of water at 0°C is heated to 100°C? (Specific heat
capacity of water = 4186 J/kg·K)
a) 1395 J/K
b) 13.95 J/K
c) 139.5 J/K
d) 419.6 J/K
Answer: a) 1395 J/K
96. Which of the following is an intensive property?
a) Mass
b) Volume
c) Internal energy
d) Specific volume
Answer: d) Specific volume
97. The work done in an isothermal expansion of an ideal gas is:
a) Positive
b) Negative
c) Zero
d) Depends on the initial and final volumes
Answer: a) Positive
98. What is the efficiency of a heat engine that absorbs 1000 J of heat and rejects 700 J of heat
in each cycle?
a) 20%
b) 30%
c) 40%
d) 50%
Answer: b) 30%
99. Which of the following is TRUE for a process at constant temperature?
a) ΔU = 0 for all systems
b) ΔH = 0 for all systems
c) ΔU = 0 for an ideal gas
d) ΔH = 0 for an ideal gas
Answer: c) ΔU = 0 for an ideal gas
100. The Third Law of Thermodynamics states that:
a) Energy is conserved
b) Entropy always increases
c) The entropy of a perfect crystal at absolute zero is zero
d) Heat always flows from hot to cold
Answer: c) The entropy of a perfect crystal at absolute zero is zero
