CHEMICAL THERMODYNAMICS MCQs

1. Which is not an intensive property?

(A) Entropy

(B) Refractive index

(C) Specific gravity

(D) Melting point

2. _____ is the branch of chemistry that deals with the basic principles governing energy changes during numerous processes.

(A) Chemical thermodynamics

(B) Wave mechanics

(C) Chemical kinetics

(D) Electrochemistry

3. ________ system is a system which can exchange energy as well as matter with its surroundings.

(A) Inert system

(B) Open system

(C) Closed system

(D) Isolated system

4. A closed system is one which can exchange with surroundings:

(A) Matter but not energy

(B) Neither matter nor energy

(C) Energy but not matter

(D) Both matter and energy

5. Which is not an extensive property?

(A) Free energy

(B) Work

(C) Entropy

(D) Volume

6. ∆H and ∆E are related as:

(A) ∆H = ∆E + P∆V

(B) ∆E = ∆H – P∆F

(C) ∆E = ∆H + ∆PV

(D) ∆H = ∆E – P∆S

7. In an isochoric process:

(A) Energy remains constant

(B) Pressure remains constant

(C) Volume remains constant

(D) Temperature remains constant

8. Which is forever true for the adiabatic expansion of a gas?

(A) Temperature rises

(B) Pressure rises

(C) Q = 0

(D) W = 0

9. A process in which no heat/mass enters or leaves the system is called:

(A) Adiabatic

(B) Isochoric

(C) Isobaric

(D) Isothermal

10. The variation of enthalpy of reaction with temperature is given by:

(A) Kirchhoff’s equation

(B) Classius-Clapayron equation

(C) Hesse’s law

(D) Arrhenius equation

11. Internal energy does not include which of the following?

(A) Energy of gravitational pull

(B) Vibrational energy

(C) Rotational energy

(D) Nuclear energy

12. Which statement is not related to applications and limitations of first law of thermodynamics?

(A) It is silent about the direction of heat

(B) This law explains why chemical reactions proceed to completion

(C) It is silent about the source of heat

(D) It does not tell us about the reversible process

13. Which statement is not related with Joule-Thomson Effect?

(A) All gases show change in temperature

(B) H and He show heating effect

(C) Joule-Thomson coefficient is defined as με = (ϱP/ϱT)H

(D) Joule-Thomson is iso-enthalpic in nature

14. Which enthalpy is forever negative?

(A) Enthalpy of formation

(B) Enthalpy of solution

(C) Enthalpy of combustion

(D) Enthalpy of melting

15. Any property magnitude independent of the amount of substance present is called a/an:

(A) Structural property

(B) Colligative property

(C) Intensive property

(D) Extensive property

16. Regarding the internal energy of the molecules, which one of the following statement is not true?

(A) It is the sum of vibrational, rotational and electronic energy

(B) Its absolute value cannot be determined

(C) It is a state function

(D) It is a path function

17. When two bodies have equality of temperature with a 3rd body, they in turn have equality of temperature with each other. This is a statement of:

(A) Nernst heat theorem

(B) First law of thermodynamics

(C) Second law of thermodynamics

(D) Zeroth law of thermodynamics

18. Which statement is not related with entropy?

(A) It is a measure of unavailable energy

(B) It is a path function

(C) It is a function of thermodynamic probability

(D) It is a measure of disorder

19. If T₁ and T₂ are the temperatures of the heat source and sink respectively, then the efficiency of the heat engine is defined as

(A) 1 – T₂ / T₁

(B) T₁ / T₂

(C) T₂ / T₁

(D) 1 + T₁ / T₂

20. The efficiency of a reversible heat engine depends only on the

(A) Temperature of the heat sink

(B) Temperature of the heat source and sink

(C) Nature of the engine fluid

(D) Temperature of the heat source

21. Which statement is not true with respect to the second law of thermodynamics?

(A) It helps in determining the direction of energy transfer

(B) It helps to know the position of chemical equilibrium

(C) It determines the conversion of heat into work

(D) It is based on Nernst heat theorem

22. The overall energy change during the Carnot cycle is

(A) Maximum

(B) Equal to Q

(C) Equal to zero

(D) Equal to W

23. Which process is not related with Carnot cycle?

(A) Isothermal expansion

(B) Adiabatic expansion

(C) Isothermal compression

(D) Isobaric compression

24. Which expression is true regarding entropy change of a reversible process?

(A) ΔS > 0

(B) ΔS = 0

(C) ΔS < 0

(D) ΔS = 1

25. Which is not a state function?

(A) Pressure

(B) Heat

(C) Temperature

(D) Volume

26. Which is true regarding the entropy of the universe?

(A) Tends towards a minimum

(B) Tends towards a maximum

(C) Tends to be zero

(D) Remains constant

27. Which causes decrease in entropy?

(A) Conversion of ice into water

(B) Rusting of iron

(C) Vaporization of camphor

(D) Precipitation of sucrose from water

28. The condensation of any gas to a liquid is expected to have _____ and a _______.

(A) A negative ΔH and a positive ΔS

(B) A positive ΔH and a negative ΔS

(C) A negative ΔH and a negative ΔS

(D) A positive ΔH and a positive ΔS

29. Total kinetic energy of a molecule of a gas is due to

(A) Translational motion

(B) Rotational motion

(C) Vibrational motion

(D) All of A, B, and C

30. At constant T and P, the change in Gibbs free energy is represented by which of the following?

(A) ΔF = ΔA – TΔS

(B) ΔF = ΔA + TΔS

(C) ΔF = ΔH – TΔS

(D) ΔF = ΔH + TΔS

31. Which does not represent the criterion of spontaneity of a reaction?

(A) ΔE ≤ 0 (at constant S and V)

(B) ΔH ≤ 0 (at constant S and P)

(C) ΔS ≤ 0 (at constant V and E)

(D) ΔF ≤ 0 (at constant T and P)

32. At constant temperature, the decrease in Helmholtz free energy is equal to which of the following?

(A) Decrease in entropy

(B) Maximum work done by the system

(C) Irreversible work done by the system

(D) Increase in entropy

33. At constant temperature and pressure, the decrease in Gibbs free energy (F) is equal to

(A) Decrease in entropy

(B) Maximum work done by the system

(C) All types of work except the work of expansion

(D) Increase in entropy

34. Enthalpy of food and fuel is measured by

(A) Monometer

(B) Bomb calorimeter

(C) Colorimeter

(D) Refractometer

35. All naturally occurring processes proceed spontaneously in a direction that leads to

(A) Decrease of entropy

(B) Increase in internal energy

(C) Decrease in free energy

(D) Increase in temperature

36. In the bomb calorimeter, the reaction is carried out at which of the following?

(A) Constant V

(B) Constant P

(C) Constant Q

(D) Constant T

37. Which law of thermodynamics helps in calculating the absolute entropies of various substances?

(A) Zeroth law

(B) First law

(C) Second law

(D) Third law

38. Which expression describes the exact relationship between standard free energy change and equilibrium constant?

(A) ΔF = RT ln K

(B) ΔF = RT in K

(C) ΔF = ΔH – TΔS

(D) ΔF = nRT ln (P₂ / P₁)

39. Which is the statement of third law of thermodynamics?

(A) Entropy of perfectly crystalline substance is zero at T = 0

(B) Entropy of a perfectly crystalline substance is zero at STP

(C) Entropy and enthalpy of a substance become equal at T = 0

(D) Free energy of a crystalline substance is zero at T = 0

40. If n₁ and n₂ represent moles of two components and µ₁ and µ₂ their chemical potentials respectively, then Gibbs-Duhem equation for this binary system is written as

(A) n₁dµ₁ = n₂dµ₂ = 0

(B) n₁dµ₁ – n₂dµ₂ = 0

(C) n₁dµ₁ + n₂dµ₂ = 0

(D) n₁dµ₁ + n₂dµ₂ > 0

41. According to which law, the enthalpy change accompanying any physical or chemical transformation approaches zero as T approaches zero?

(A) Helmholtz law

(B) Third law of thermodynamics

(C) Second law of thermodynamics

(D) Nernst heat theorem

42. Which statement is false regarding process of evaporation of a liquid?

(A) No change in free energy

(B) Free energy decreases

(C) Entropy increases

(D) Enthalpy increases

43. The link between classical thermodynamics and quantum mechanics is provided by which of the following laws?

(A) Matrix mechanics

(B) Boltzmann law

(C) Statistical mechanics

(D) Wave mechanics

44. In statistical mechanics, there exists a function which contains all the information about a macroscopic system. This function is called _____ .

(A) Distribution function

(B) Partition function

(C) Eigen function

(D) Wave function

45. Which has the highest value?

(A) Electronic partition function

(B) Translational partition function

(C) Vibrational partition function

(D) Rotational partition function

46. In an adiabatic system, if work is done, the temperature must be _____.

(A) Increase

(B) Decrease

(C) Remain the same

(D) None of A, B, and C

47. In which substance(s) ΔE = ΔH and no PV work?

(A) Both liquids and solids

(B) Liquids

(C) Gases

(D) Solids only

48. The heat flow of a system under isochoric conditions is a direct measurement of which of the following?

(A) Work

(B) ΔE

(C) ΔH

(D) ΔF

49. According to Le-Chatelier’s principle, the addition of heat to the following reaction CO2 + 2H2O → CH4 + 2O2 will cause it to shift to right. The reaction can therefore be described as

(A) Spontaneous

(B) Adiabatic

(C) Exothermic

(D) Endothermic

50. For the reaction CaCO3 → CaO + CO2, when taking place at higher temperature, which is true?

0, ΔF < 0')"> (A) ΔH < 0, ΔF ≥ 0

0, ΔF < 0')"> (B) ΔH ≤ 0, ΔF < 0

0, ΔF < 0')"> (C) ΔS > 0, ΔF < 0

0, ΔF < 0')"> (D) ΔF ≥ 0, ΔA ≥ 0

51. At constant volume the heat of a reaction is represented by

(A) ΔF

(B) ΔH

(C) ΔA

(D) ΔE

52. Which is true for adiabatic reversible process?

(A) ΔQ = 0

(B) ΔP = 0

(C) ΔW = 0

(D) ΔT = 0

53. ______ is the thermodynamic parameter, which is a state function and is measure of disorder of a system.

(A) Entropy

(B) Enthalpy

(C) Free energy

(D) Internal energy

54. One calorie is equivalent to

(A) 8.314 J

(B) 41.84 J

(C) 4.184 J

(D) 83.14 J

55. The statement that heat cannot flow spontaneously from a colder to a hotter body is the result of which of the following?

(A) The second law of thermodynamics

(B) Henry’s law

(C) The third law of thermodynamics

(D) The first law of thermodynamics

56. Internal energy of a given mass of an ideal gas depends upon

(A) Temperature

(B) Pressure

(C) Volume

(D) All of A, B, and C

57. Which provides physical significance of ΔF?

(A) ΔF = Wuseful

(B) ΔF = Wmax

(C) ΔF = Wuseful

(D) ΔF = ΔH – TΔS

58. For a spontaneous but endothermic process

(A) ΔF must be positive

(B) ΔS must be greater than zero

(C) TΔS must be negative

(D) All of A, B, and C

59. Use of thermometer is based on which law of thermodynamics?

(A) 2nd Law

(B) 1st law

(C) Zeroth law

(D) 3rd law

60. ΔG = ΔG°, when the reaction quotient (Q) is

(A) 0

(B) <1

(C) >1

(D) 1

61. For a reversible process, what is the entropy change?

(A) ΔS > 0

(B) ΔS < 0

(C) All of A, B, and C

(D) ΔS = 0

62. At equilibrium the free energy change is

(A) ΔG = 0

(B) ΔG < 0

(C) ΔG > 0

(D) All of A, B, and C

63. Which is true for first law of thermodynamics?

(A) ΔE = Q + PV

(B) ΔE = Q – PV

(C) ΔE = Q – W

(D) ΔE = Q + W

64. If ΔG is zero for a reaction then _____.

(A) ΔH = 0

(B) K = 1

(C) ΔS = 0

(D) K = 0

65. Which occurs when a solid melts?

(A) Decrease in free energy

(B) Decrease in entropy

(C) Decrease in internal energy

(D) Increase in internal energy

66. Which makes the motion of perpetual motion machine a physical impossibility?

(A) Zeroth law of thermodynamics

(B) First law of thermodynamics

(C) Third law of thermodynamics

(D) Second law of thermodynamics