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Thermo-Chemistry Online Mcqs Test

Mustansar KhanLast Updated: October 14, 2025

Important Thermo Chemistry Question and Answer

Total Questions:	108
Time Allowed:	60 Minutes
Total Marks:	108
How to Attempt Test:	Please choose the right Option in MCQ-type question.
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Thermo Chemistry Practice Test Online With Explanation

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Page 1 of 5

Chemistry

1. Which one is not state function?

Internal energy

Work

Gibbs free energy

Enthalpy

2. In general, for exothermic reactions to be spontaneous

Temperature should be zero

Temperature should be high

Temperature should be low

Temperature has no effect

3. For a melting of a solid at 25°C, the fusion process requires energy equivalent to 2906 Joules to be added to system considering the process to be reversible at fusion point, the entropy change of the process is

2.33 JK¯¹

11.272 JK¯¹

Insufficient data

9.75 JK¯¹

4. For a given process, the heat changes at constant pressure (q_p) and at constant volume (q_v) are related to each other as:

5. Evaporation of water is

An endothermic change

A process accompanied by chemical reaction

A process where no heat changes occur

An exothermic change

6. A material or a collection of materials which is under study is called

Surrounding

Any substance

System

State function

7. An endothermic reaction is one in which

Heat is converted into electricity

Heat is absorbed

Heat is converted into mechanical work

Heat is evolved

8. The enthalpies of combustion of carbon and carbon monoxide are -390 kJ mol¯¹ and -278 kJ mol¯¹ respectively. The enthalpy of formation of carbon monoxide is

112 kJ mol¯¹

-112 kJ mol¯¹

-668 kJ mol¯¹

668 kJ mol¯¹

9. The law of Lavoisier and Laplace illustrates

The principle of conservation of energy

Equivalent of mechanical and chemical energy

The principle of conservation of matter

Equivalence of mechanical and thermal energy

10. The law of thermodynamics that provides the basis for the determination of absolute entropy of substance is

Third law

First law

Zeroth law

Second law

11. Enthalpy of formation of HF and HCl are – 161 kJ and -92 kJ respectively. Which of the following statements is incorrect?

The affinity of fluorine to hydrogen is greater than the affinity of chlorine to hydrogen

HF and HCl are endothermic compounds

HF is more stable than HCl

HCl is more stable than HF

12. Which law among the following has same net change whether it takes place directly or indirectly?

Graham’s law

Hess’s law

Henry’s law

Boyle’s law

13. The bond dissociation energies of H₂, CL₂ and HCl are 104, 58 and 103 kcal respectively. The enthalpy of formation of HCl gas will be

-44 kcal

-22 kcal

-88 kcal

-11 kcal

14. All of the following are state function except

15. Most of the thermodynamic parameters are

Surrounding

State function

Phase

System

16. When enthalpy of reactants is higher than products, then reaction will be

Spontaneous

Exothermic

Non-spontaneous

Endothermic

17. Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are -382.64kJ mol¯¹ and -145.6kJ¯¹ mol¯¹ respectively. Standard Gibbs energy change for the same reaction at 298 K is

-439.3 kJ mol¯¹

-221.1 kJ mol¯¹

-523.3 kJ mol¯¹

-339.3 kJ mol¯¹

18. A spontaneous change means

A lowering of energy

An increase in internal energy

No energy change

A lowering of free energy

19. Mechanical work is especially important in systems that contain

Gases

Solid-liquid

Liquid-liquid

Solid-solid

20. Choose the S.I units for molar heat capacity among the following

Joule cm¯¹ deg¯¹

Joule deg¯¹ mol¯¹

Joule deg¯¹ Kg¯¹

Joule deg¯¹ atom¯¹

21. The heats evolved in combustion of rhombic and monoclinic sulphur are -70960 and -71030 cal mol¯¹ respectively. What will be heat of conversion of rhombic sulphur to monoclinic?

+70 calories

-70 calories

71030 calories

70960 calories

22. A mixture of ice and water contains 60 g of ice and water. If 60 J of heat energy is removed from this mixture, some of the

Water will vaporize

Ice will melt

Ice will sublime

Water will freeze

23. The apparatus used to measure the enthalpy of combustion of a substance is

All above

Copper calorimeter

Bomb calorimeter

Glass calorimeter

24. Conversion of copper hydroxide into copper oxide and water is an example of

Thermal decomposition

Combustion

Neutralization

Respiration

25. If internal energy of the system is increased

Change in state of the system is increased

Chemical reaction may take place

All

Temperature of the system may rise

Page 2 of 5

26. Unit of heat is SI system is

KCaL

Cal

27. All the naturally occurring processes proceed spontaneously in a direction which lead to

Decrease of entropy

Decrease of free energy

Increase of free energy

Increase of enthalpy

28. The ∆H values for reaction C + ½ O₂ → CO and CO + ½ O₂ → CO₂ are 100 and 200 kJ respectively. The heat of reaction for C + O₂ → CO₂ will be

300 kJ

50 kJ

150 kJ

100 kJ

29. An adiabatic expansion of an ideal gas always has

Q = 0

∆H = 0

W = 0

Decrease in temperature

30. A particular reaction has a negative value for the energy change. Then at ordinary temperature

It has a large – ve value for the entropy change

It has small + ve value for enthalpy change

It has a + ve value for the entropy change and a – ve value for the enthalpy change

It has a large + ve value for enthalpy change

31. The enthalpies of all elements in their standard states are

Unity

Negative

Zero

Positive

32. Total energy depends upon the state of system

Free energy of reaction

Entropy of reaction

All above

Enthalpy

33. Which of the following is not correct?

The heat of reaction at constant volume is denoted by ∆E.

Neutralization is always exothermic

Dissolution on NH₄Cl in excess of water is an endothermic process

The absolute value of enthalpy (H) can be determined experimentally

34. When enthalpy and entropy change for a chemical reaction are – 2.5 x 10³ cals and 7.4 cals deg¯¹ respectively. Predict that reaction at 298 K is

Reversible

Spontaneous

Irreversible

Non-spontaneous

35. In order to decompose 9 g of water 142.5 kJ of heat is required. Hence enthalpy of formation of water is

-285 kJ

+285 kJ

-142.5 kJ

+142.5 kJ

36. The amount of heat which is involved during the completion of a chemical reaction at 25°C and 1 atmospheric pressure is called

Hat of formation

Heat of neutralization

Enthalpy of reaction

Heat of combustion

37. The reason of kinetic energy of the molecules of a gaseous substance among the following is

The sum of all motions which are possible

Vibrational motion

Rotational motion

Translational motion

38. Change in enthalpy of a system can be calculated by following relationship

∆H = ∆E + Pv

∆H = ∆E + d

∆H = ∆E – PV

∆H = ∆E – d

39. An exothermic reaction is one in which the reacting substances

Have less energy than the products

Have the same energy as the products

Have more energy than the products

Are at a higher temperature than the products

40. Which statement describes characteristics of an endothermic reaction?

The sign of H is positive and the products a have more potential energy than the reactant

The sign of H is positive, and the products have less potential energy than the reactants

The sign of H is negative, and the products have less potential energy than the reactants

The sign of H is negative, and the products have more potential energy than the reactants

41. Which of the following unit represent the largest amount of energy?

Erg

Calorie

Electron – volt

Joule

42. Endothermic changes are indicated through

Breaking of chemical bonds

Making of chemical bond

All of these

Burning of carbon

43. What is the entropy change (in JK¯¹ mol¯¹) when one mole of ice is converted into water at 0°C? (The enthalpy change for the conversion of ice to liquid water is 6.0 kJ mol¯¹ at 0°C)

2.013

20.13

2.198

21.98

44. If at 298 K the bond energies of C-H, C-C, C=C and H-H bonds are respectively 414, 347, 615 and 435 kJ mol¯¹, the value of enthalpy change for the reaction H₂C = CH₂(g) + H₂(g) → H₃C – CH₃(g) at 298 K will be

+250 kJ

-125 kJ

+125 kJ

-250 kJ

45. The enthalpy of formation of carbon monoxide will be

2x – y

2x – y/2

Y – 2x

Y – 2x/2

46. Free energy change for a reversible process is:

Equal to zero

Unpredictable

47. 1 mole of H₂SO₄ is mixed with 2 mole of NaOH. The heat evolved will be

2 x 57.3 kJ

Cannot be predicted

57.3/2 kJ

57.3 kJ

48. The branch of chemistry which deals with thermal energy change in chemical reaction is called

Mechanics

Thermochemistry

Thermodynamics

Chemical kinetics

49. Pumping of water uphill is

Irreversible process

None of these

Non spontaneous

Spontaneous process

50. Which of the following value of ∆Hf’ represent that the product is least stale?

+21.4 kcal mol¯¹

+64.8 kcal mol¯¹

-231.6 kcal mol¯¹

-94.0 kcal mol¯¹

Page 3 of 5

51. For the reaction NaOH + HCl → NaCl + H₂O the change in enthalpy is called

Heat of sublimation

Heat of reaction

Heat of neutralization

Heat of combustion

52. The enthalpies of combustion of carbon and carbon monoxide are -383.5 and -283 kJ mol¯¹ respectively. The enthalpy of formation of carbon monoxide per mole is

110.5 kJ

-676.5 kJ

676.5 kJ

-110.5 kJ

53. Total energy of a system is

P.E + mechanical energy

K.E + heat energy

P.E + K.E

P.E + heat energy

54. 10.16 g of graphite is burnt in a bomb calorimeter and the temperature rise recorded is 3.78 K. Calculate the enthalpy of combustion of graphite if the heat capacity is 86.02 KJ K¯¹

395 KJ/mole

-27 KJ/mole

190 KJ/mole

386 KJ/mole

55. Reaction in which heat is evolved

Exothermic

Non-spontaneous

Endothermic

Spontaneous

56. The energy required to break 1 mole of bonds to form neutral atom is

Bond strength

Bond length

None of these

Bond energy

57. The unit which indicates the largest amount of energy is

Electron – volt

Joule

Calorie

Erg

58. The molar heat capacity of water at constant pressure, Cᵨ, is 75 JK¯¹ mol¯¹. When 1.0 kJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is

4.8 K

2.4 K

6.6 K

1.2 K

59. When 50 cm³ of 0.2 n H₂SO₄ is mixed with 50 cm³ of 1 N KOH, the heat liberated is

573 J

573 kJ

57.3 kJ

11.46 kJ

60. When a bond breaks

No change in heat contents takes place

Heat is absorbed

Temperature increases

Heat is evolved

61. One mole of an ideal gas expands isothermally to ten times its original volume. The change in entropy is

10.0 R

100.0 R

2.303 R

0.1 R

62. Form the above data, the standard heat of formation of KOH in kcal mol¯¹ is

68 + 48 + 14

68 – 48 + 14

– 68 + 48 – 14

– 68 – 48 + 14

63. Quantity of heat evolved or absorbed during reaction measure according to

∆E = q + w

∆H = ∆E + P∆V

P∆V + nRT

Q = m x X x ∆ T

64. Which of the following statement is contrary to first law of thermodynamics?

Continuous production of mechanical work without supplying an equivalent amount of heat energy

One form of energy can be transferred to an equivalent amount of the kind of energy

Work done is independent of its path

An equivalent amount of heat energy can neither be created nor destroyed

65. In endothermic reactions, the heat content of the

Reactants is more than that of products

Products is more than that of reactants

Both a and b

Reactants and products are equal

66. Which of the following units represents largest amount of energy?

Electron vol

Calorie

Joule

Erg

67. ______ is the study about energy of a chemical system

Thermodynamics

Thermochemistry

Kinetics

Stoichiometry

68. Enthalpy of a reaction can be measured by

Barometer

Glass calorimeter

Thermometer

Manometer

69. The heat required to raise the temperature of a body by 1 K is called

Thermal capacity

Specific heat

None of these

Water equivalent

70. The reaction is spontaneous if the cell potential is

Negative

Positive

Infinite

Zero

71. The net change in energy in a chemical reaction is same whether it takes place directly or indirectly is

Hess’s law

Graham’s law

Henry’s law

Charles’s law

72. The S.I unit of heat and energy is

Watt

Calorie

None of these

Joules

73. In thermodynamics which one of the following is not an intensive property?

Pressure

Temperature

Density

Volume

74. Calorie is equivalent to

0.4184 J

418.4 J

4.184 J

41.84 J

75. If internal energy of a system is increased

Change in state of system can occur

Temperature of the system may rise

All

Chemical reaction can take place

Page 4 of 5

76. Total energy of a system is

P.E. + heat energy

K.E, + heat energy

P.E, + K.E.

P.E, + mechanical energy

77. If an endothermic reaction is allowed to take place very rapidly in the air, the temperature of the surrounding air

Increases

Decreases

Remains same

Remains constant

78. A macroscopic property of a system which describes the initial and final state of the system is called

Physical property

Energy of the system

Chemical property

State function

79. The branch of science which deals with energy transformation is known as

Thermodynamics

Thermochemistry

Photochemistry

Kinetics

80. Two fundamental ways to transfer energy are

Heat and work

Pressure and temperature

Pressure and volume

Heat and volume

81. The value of ∆Hо₋н is 109 kcal mol¯¹. Then formation of one mole of water in gaseous state form H(g) and O(g) is accompanied by

Unpredictable

Absorption of 218 kcal of energy

Release of 218 kcal of energy

Release of 109 kcal of energy

82. Two fundamental ways to transfer energy are

Heat and work

Pressure and volume

Heat and volume

Pressure and temperature

83. Enthalpy of combustion for food, fuel and other compounds can be measured accurately by

Monometer

Thermometer

Bomb Calorimeter

Glass Calorimeter

84. Four containers hold the following quantity at the same temperature. Which one has the highest heat capacity?

2 kg H₂O

1 kg H₂O

3 kg H₂O

4 kg H₂O

85. For a system in equilibrium, ∆ G = 0, under conditions of constant

Temperature and pressure

Temperature and volume

Pressure and volume

Energy and volume

86. Sublimation, vaporization, melting and p photosynthesis all are examples of

Chemical process

Biochemical process

Endothermic process

Physical process

87. Which one is not a state function?

Work

Enthalpy

Internal energy

Gibbs free energy

88. What would be the heat released when an aqueous solution containing 0.5 mole of HNO₃ is mixed with 0.3 mol of OH¯ (enthalpy of neutralization is -57.1 kJ)

17.1kJ

45.7 kJ

28.5 kJ

1.7 kJ

89. In measurement of melting point of solid, the leaker used will be

Phase

System

Surrounding

State

90. System in which there is no exchange of matter, work or energy from surroundings is

Isothermal

Adiabatic

Isolated

Closed

91. A chemist heated a balloon by supplying 600 J of heat. The balloon expands doing 200 J of work against the atmospheric pressure. The change in internal energy of

-400J

= + k319

0 J

= - k719

92. Most of the reactions which give stable products are

None of these

Isothermal

Exothermic

Endothermic

93. Heat exchanged in a chemical reaction at constant temperature and pressure is called

Internal energy change

Entropy change

Free energy change

Enthalpy change

94. The best characteristic of spontaneous reactions among the following is that

None of these

It is irreversible

It is reversible

It is not irreversible

95. What type of chemical reaction absorbs energy and requires energy for the reaction occur?

Exothermic

Synthesis

Both a and b

Endothermic

96. When water is added to quick lime, the reaction is

Exothermic

Endothermic

Photochemical

Explosive

97. When enthalpy of reactants is higher than product then reaction will be

Endothermic

Non-spontaneous

Spontaneous

Exothermic

98. For a reaction to occur spontaneously

∆ H must be unity

∆ H must be zero

∆ H must be negative

∆ H must be positive

99. A cylinder of gas supplied by PSO is assumed to contain 14 kg of butane. If a normal family requires 20,000 kJ of energy per day for cooking, butane gas in the cylinder last for ……. Days (∆Hc of C₄H₁₀ = -2658 kJ per mole)

50 days

32 days

20 days

15 days

100. The internal energy change when a system goes form state A to B is 40 kJ.mol. If the system goes from A to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy?

< 40 kJ

Zero

> 40 kJ

40 kJ

Page 5 of 5

101. If coefficients of a chemical equation are doubled, the enthalpy change will

None of these

Be double

Not change

Be half

102. What type of reaction releases energy and does not require initial energy to occur?

Both a and b

Decomposition

Exothermic

Endothermic

103. Hess’s law deals with

Changes in heat or reaction

Equilibrium constant

Rate of reaction

Influence of pressure on volume of a gas

104. One of the statement about Born Haber cycle is correct. Which is that statement?

Heat of formation of the product and lattice energy of the substance can be calculated simultaneously

The energy change in a cyclic process is not zero

The lattice energy of the crystalline substances can be calculated easily

Born Haber cycle is different from Hess’s law

105. Which type of reactions cannot occur spontaneously?

Both a and b

Exothermic

Endothermic

Neither

106. Unit of heat in S.I system is

Cal

Kcal

107. Burning of coal in air is initiated by a spark and it is an example of spontaneous reaction because

None of these

Burning of coal in air releases large amount of energy

Coal and air react giving a reversible reaction

Burning of coal is and endothermic process

108. C (diamond) → C(Graphite), ∆ H = -ve. This show that

Stability cannot to predicated

Graphite has more energy than diamond

Both are equally stable

Graphite is more stable than diamond

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Mustansar KhanLast Updated: October 14, 2025

Thermo-Chemistry Online Mcqs Test

Important Thermo Chemistry Question and Answer

Thermo Chemistry Practice Test Online With Explanation

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