Chemical Engineering Thermodynamics 1000+ MCQ with answer for ESIC

1. The work done in isothermal compression compared to that in adiabatic compression will be
A. Less
B. More
C. Same
D. More or less depending upon the extent of work done
Answer : B

2. Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the
A. Calorific value
B. Heat of reaction
C. Heat of combustion
D. Heat of formation
Answer : C

3. The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is
A. Less pronounced
B. More pronounced
C. Equal
D. Data insufficient, can't be predicted
Answer : B

4. Absorption/evolution of heat during conversion of a substance from one allotropic form to another is termed as the heat of
A. Sublimation
B. Fusion
C. Transition
D. Vaporisation
Answer : C

5. C_v for an ideal gas
A. Does not depend upon temperature
B. Is independent of pressure only
C. Is independent of volume only
D. Is independent of both pressure and volume
Answer : D

6. The rate at which a substance reacts is proportional to its active mass and the rate of a chemical reaction is proportional to the product of active masses of the reacting substances. This is the
A. Lewis-Randall rule
B. Statement of Van't Hoff Equation
C. Le-Chatelier's principle
D. None of these
Answer : D

7. After throttling, gas temperature
A. Decreases
B. Increases
C. Remain same
D. May increase or decrease; depends on the nature of the gas
Answer : A

8. When a gas is expanded from high pressure region to low pressure region; temperature change occurs. This phenomenon is related to the
A. Gibbs-Duhem equation
B. Gibbs-Helmholtz equation
C. Third law of thermodynamics
D. Joule-Thomson effect
Answer : D

9. Standard temperature and pressure (S.T.P.) is
A. 0°C and 750 mm Hg
B. 15°C and 750 mm Hg
C. 0°C and 1 kgf/cm2
D. 15°C and 1 kgf/cm2
Answer : A

10. Which of the following is not an extensive property?
A. Free energy
B. Entropy
C. Refractive index
D. None of these
Answer : C

11. Compressibility factor (i.e., the ratio of actual volume of gas to the volume predicted by ideal gas law) for all gases are
A. Always greater than one
B. Same at the same reduced temperature
C. Same at the same reduced pressure
D. Both (B) & (C)
Answer : D

12. 1st law of thermodynamics is nothing but the law of conservation of
A. Momentum
B. Mass
C. Energy
D. None of these
Answer : C

13. The fugacity of a gas in a mixture is equal to the product of its mole fraction and its fugacity in the pure state at the total pressure of the mixture. This is
A. The statement as per Gibbs-Helmholtz
B. Called Lewis-Randall rule
C. Henry's law
D. None of these
Answer : B

14. What is the value of maximum COP in case of absorption refrigeration, if refrigeration provided is at temperature, T_R (where, T₁ and T₂ are source & surrounding temperatures respectively.)?
A. T_R/(T₂ - T_R) × (T₁ - T₂)/T₁
B. T_R/(T₂ - T_R) × T₁/(T₁ - T₂)
C. T_R/(T₁ - T_R) × (T₁ - T₂)/T₁
D. None of these
Answer : A

15. The following heat engine produces power of 100,000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is absorbed from the hot reservoir is
A. 100,000 kW
B. 160,000 kW
C. 200,000 kW
D. 320,000 kW
Answer : D

16. For an ideal gas, the enthalpy
A. Increases with rise in pressure
B. Decreases with rise in pressure
C. Is independent of pressure
D. Is a path function
Answer : C

17. What is the number of degrees of freedom for liquid water in equilibrium with a mixture of nitrogen and water vapor?
A. 2
B. 0
C. 3
D. 1
Answer : A

18. For a constant volume process __________ by the system is used only to increase the internal energy.
A. Heat absorbed
B. Work done
C. Both (A) & (B)
D. Neither (A) nor (B)
Answer : A

19. Which of the following is an undesirable characteristic of a refrigerant?
A. It should be non-explosive
B. It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils
C. Its vapor pressure at the condenser temperature should be very high
D. None of these
Answer : B

20. Boiling of liquid is accompanied with increase in the A. Vapor pressure
B. Specific Gibbs free energy
C. Specific entropy
D. All (A), (B) and (C)
Answer : A

21. The expression for entropy change, ?S = n C_p . ln (T₂/T₁), is valid for the __________ of a substance.
A. Simultaneous pressure & temperature change
B. Heating
C. Cooling
D. Both (B) and (C)
Answer : D

22. In jet refrigerators, the refrigerating fluid is practically always
A. Water
B. Ammonia
C. Freon
D. Brine
Answer : A

23. The equation Tds = dE - PdV applies to
A. Single phase fluid of varying composition
B. Single phase fluid of constant composition
C. Open as well as closed systems
D. Both (B) and (C)
Answer : D

24. A system is said to be isopiestic, if there is no __________ change.
A. Temperature
B. Pressure
C. Volume
D. None of these
Answer : B

25. The compressibility factor of a gas is given by (where, V₁ = actual volume of the gas V₂ = gas volume predicted by ideal gas law)
A. V₁/V₂
B. V₂/V₁
C. V₁ - V₂
D. V₁.V₂
Answer : A

26. A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system
A. its internal energy (U) decreases and its entropy (S) increases
B. U and S both decreases
C. U decreases but S is constant
D. U is constant but S decreases
Answer : B

27. Which of the following represents the Virial equation of state?
A. T = [RT/(V- b)] - [a/?T. V(V + b)]
B. PV/RT = 1 + (B/V) + (C/V²) + ……
C. n₁u₂ + ?₂?₁ = 0
D. None of these
Answer : B

28. Pick out the wrong statement.
A. A refrigeration cycle violates the second law of thermodynamics
B. Refrigeration cycle is normally represented by a temperature vs. entropy plot
C. In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases
D. One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW
Answer : A

29. Law of corresponding states says that
A. Two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same
B. The surface of separation (i. e. the meniscus) between liquid and vapour phase disappears at the critical temperature
C. No gas can be liquefied above the critical temperature, howsoever high the pressure may be.
D. The molar heat of energy of gas at constant volume should be nearly constant (about 3 calories)
Answer : A

30. Joule-Thomson co-efficient which is defined as, ? = (?T/?P)H = 1/Cp (?H/?T)P, changes sign at a temperature known as inversion temperature. The value of Joule-Thomson co-efficient at inversion temperature is
A. 0
B. ?
C. +ve
D. -ve
Answer : A

31. Compressibility factor for almost all the gases are approximately same at the same
A. Pressure and temperature
B. Reduced pressure and reduced temperature
C. Critical pressure and critical temperature
D. None of these
Answer : B

32. The chemical potential of any constituent of an ideal solution depends on the __________ of the solution.
A. Temperature
B. Pressure
C. Composition
D. All (A), (B) and (C)
Answer : D

33. Pick out the wrong statement.
A. The net change in entropy in any reversible cycle is always zero
B. The entropy of the system as a whole in an irreversible process increases
C. The entropy of the universe tends to a maximum
D. The entropy of a substance does not remain constant during a reversible adiabatic change
Answer : D

34. The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible __________ process.
A. Isobaric
B. Isothermal
C. Adiabatic
D. None of these
Answer : B

35. Gibbs free energy per mole for a pure substance is equal to the
A. Latent heat of vaporisation
B. Chemical potential
C. Molal boiling point
D. Heat capacity
Answer : B

36. Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is
A. 1
B. 2
C. 3
D. 4
Answer : B

37. For equilibrium process (i.e. reversible) in an isolated system
A. ds = 0
B. ds < 0
C. ds > 0
D. ds = Constant
Answer : A

38. Gibbs free energy at constant pressure and temperature under equilibrium conditions is
A. ?
B. 0
C. Maximum
D. Minimum
Answer : D

39. Helmholtz free energy (A) is defined as
A. A = H - TS
B. A = E - TS
C. A = H + TS
D. None of these
Answer : B

40. Gibbs free energy (G) is represented by, G = H - TS, whereas Helmholtz free energy, (A) is given by, A = E - TS. Which of the following is the Gibbs-Helmholtz equation?
A. [?(G/T)/?T] = - (H/T₂)
B. [?(A/T)/?T]_V = - E/T₂
C. Both (A) and (B)
D. Neither (A) nor (B)
Answer : C

41. There is a change in __________ during the phase transition.
A. Volume
B. Pressure
C. Temperature
D. All a, b & c
Answer : A

42. Pick out the extensive property out of the following.
A. Surface tension
B. Free energy
C. Specific heat
D. Refractive index
Answer : B

43. In an irreversible process
A. Tds = dE - dW = 0
B. dE - dW - Tds = 0
C. Tds - dE + dW < 0
D. Tds - dT + dW < 0
Answer : C

44. The internal energy of a gas obeying P (V - b) RT (where, b is a positive constant and has a constant C_v), depends upon its
A. Pressure
B. Volume
C. Temperature
D. All (A), (B) & (C)
Answer : C

45. With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure
A. Increases
B. Decreases
C. Remain same
D. Decreases linearly
Answer : A

46. A large iceberg melts at the base, but not at the top, because of the reason that
A. Ice at the base contains impurities which lowers its melting point
B. Due to the high pressure at the base, its melting point reduces
C. The iceberg remains in a warmer condition at the base
D. All (A), (B) and (C)
Answer : B

47. Enthalpy changes over a constant pressure path are always zero for __________ gas.
A. Any
B. A perfect
C. An easily liquefiable
D. A real
Answer : B

48. If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.
A. 100
B. 50
C. 205
D. 200
Answer : D

49. (?H/?T)_P is the mathematical expression for
A. C_V
B. Entropy change
C. Gibbs free energy
D. None of these
Answer : D

50. What happens in a reversible adiabatic compression?
A. Heating occurs
B. Cooling occurs
C. Pressure is constant
D. Temperature is constant
Answer : A