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. Most of the reactions which give stable products are

Isothermal

Endothermic

None of these

Exothermic

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

Unity

Zero

Positive

Negative

3. The law of Lavoisier and Laplace illustrates

Equivalence of mechanical and thermal energy

Equivalent of mechanical and chemical energy

The principle of conservation of energy

The principle of conservation of matter

4. Unit of heat is SI system is

KCaL

Cal

5. All of the following are state function except

6. 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)

21.98

2.198

20.13

2.013

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

Glass calorimeter

All above

Bomb calorimeter

Copper calorimeter

8. Which type of reactions cannot occur spontaneously?

Exothermic

Both a and b

Neither

Endothermic

9. 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

0 J

= + k319

-400J

= - k719

10. 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

11. Endothermic changes are indicated through

Breaking of chemical bonds

Burning of carbon

All of these

Making of chemical bond

12. In general, for exothermic reactions to be spontaneous

Temperature has no effect

Temperature should be high

Temperature should be zero

Temperature should be low

13. Most of the thermodynamic parameters are

State function

Phase

Surrounding

System

14. 1 mole of H₂SO₄ is mixed with 2 mole of NaOH. The heat evolved will be

Cannot be predicted

57.3/2 kJ

2 x 57.3 kJ

57.3 kJ

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

-94.0 kcal mol¯¹

+64.8 kcal mol¯¹

-231.6 kcal mol¯¹

+21.4 kcal mol¯¹

16. 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 freeze

Water will vaporize

Ice will sublime

Ice will melt

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

HF is more stable than HCl

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

HCl is more stable than HF

HF and HCl are endothermic compounds

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

Thermochemistry

Stoichiometry

Thermodynamics

Kinetics

19. Pumping of water uphill is

Non spontaneous

None of these

Spontaneous process

Irreversible process

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

Surrounding

Any substance

System

State function

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

Temperature

Density

Pressure

Volume

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

Erg

Joule

Electron – volt

Calorie

23. Total energy of a system is

P.E. + heat energy

P.E, + mechanical energy

K.E, + heat energy

P.E, + K.E.

24. 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

Release of 109 kcal of energy

Absorption of 218 kcal of energy

Unpredictable

Release of 218 kcal of energy

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

4 kg H₂O

2 kg H₂O

3 kg H₂O

1 kg H₂O

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26. 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

1.2 K

6.6 K

2.4 K

27. Two fundamental ways to transfer energy are

Heat and work

Pressure and temperature

Heat and volume

Pressure and volume

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

Graphite is more stable than diamond

Stability cannot to predicated

Both are equally stable

Graphite has more energy than diamond

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

It has a large + ve value for enthalpy 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 the entropy change

30. Calorie is equivalent to

41.84 J

0.4184 J

418.4 J

4.184 J

31. Reaction in which heat is evolved

Spontaneous

Non-spontaneous

Endothermic

Exothermic

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

Hess’s law

Henry’s law

Boyle’s law

Graham’s law

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

Thermodynamics

Kinetics

Thermochemistry

Photochemistry

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

Physical property

State function

Chemical property

Energy of the system

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

Temperature and volume

Energy and volume

Pressure and volume

Temperature and pressure

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

Endothermic

Exothermic

Both a and b

Synthesis

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

∆H = ∆E – PV

∆H = ∆E + Pv

∆H = ∆E + d

∆H = ∆E – d

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

Glass Calorimeter

Monometer

Thermometer

Bomb Calorimeter

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

Surrounding

State

Phase

System

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

First law

Zeroth law

Second law

Third law

41. Which one is not a state function?

Enthalpy

Internal energy

Gibbs free energy

Work

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

Calorie

Watt

None of these

Joules

43. 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

-221.1 kJ mol¯¹

-339.3 kJ mol¯¹

-439.3 kJ mol¯¹

-523.3 kJ mol¯¹

44. 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

-668 kJ mol¯¹

668 kJ mol¯¹

-112 kJ mol¯¹

45. 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

110.5 kJ

-676.5 kJ

676.5 kJ

46. Mechanical work is especially important in systems that contain

Solid-solid

Solid-liquid

Liquid-liquid

Gases

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

Remains same

Remains constant

Increases

Decreases

48. Total energy depends upon the state of system

All above

Enthalpy

Free energy of reaction

Entropy of reaction

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

Erg

Electron vol

Calorie

Joule

50. For a reaction to occur spontaneously

∆ H must be zero

∆ H must be positive

∆ H must be unity

∆ H must be negative

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51. Which of the following is not correct?

Neutralization is always exothermic

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

Dissolution on NH₄Cl in excess of water is an endothermic process

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

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

Isothermal

Adiabatic

Isolated

Closed

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

Heat of combustion

Hat of formation

Heat of neutralization

Enthalpy of reaction

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

+285 kJ

-142.5 kJ

-285 kJ

+142.5 kJ

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

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

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

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

Work done is independent of its path

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

Joule deg¯¹ atom¯¹

Joule deg¯¹ mol¯¹

Joule cm¯¹ deg¯¹

Joule deg¯¹ Kg¯¹

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

0.1 R

100.0 R

2.303 R

10.0 R

58. In endothermic reactions, the heat content of the

Products is more than that of reactants

Reactants is more than that of products

Reactants and products are equal

Both a and b

59. 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

-125 kJ

-250 kJ

+250 kJ

+125 kJ

60. Which one is not state function?

Internal energy

Gibbs free energy

Work

Enthalpy

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

Combustion

Respiration

Neutralization

Thermal decomposition

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

Endothermic

Exothermic

Both a and b

Decomposition

63. 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

-88 kcal

-11 kcal

-22 kcal

64. An adiabatic expansion of an ideal gas always has

Q = 0

∆H = 0

W = 0

Decrease in temperature

65. Free energy change for a reversible process is:

Equal to zero

Unpredictable

66. Enthalpy of a reaction can be measured by

Manometer

Thermometer

Glass calorimeter

Barometer

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

Have less energy than the products

Are at a higher temperature than the products

Have more energy than the products

Have the same energy as the products

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

573 kJ

11.46 kJ

57.3 kJ

573 J

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

Endothermic process

Chemical process

Biochemical process

Physical process

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

Spontaneous

Exothermic

Endothermic

Non-spontaneous

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

Heat of combustion

Heat of neutralization

Heat of sublimation

Heat of reaction

72. A spontaneous change means

No energy change

An increase in internal energy

A lowering of free energy

A lowering of energy

73. Which statement describes characteristics of an endothermic reaction?

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

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

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

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

Joule

Electron – volt

Calorie

Erg

75. 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?

70960 calories

71030 calories

-70 calories

+70 calories

Page 4 of 5

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

Free energy change

Entropy change

Enthalpy change

Internal energy change

77. If internal energy of the system is increased

Temperature of the system may rise

Change in state of the system is increased

Chemical reaction may take place

All

78. Unit of heat in S.I system is

Cal

Kcal

79. When a bond breaks

Heat is absorbed

Temperature increases

No change in heat contents takes place

Heat is evolved

80. Two fundamental ways to transfer energy are

Heat and work

Pressure and volume

Pressure and temperature

Heat and volume

81. 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

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

∆E = q + w

∆H = ∆E + P∆V

Q = m x X x ∆ T

P∆V + nRT

83. 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

9.75 JK¯¹

11.272 JK¯¹

Insufficient data

2.33 JK¯¹

84. 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)

45.7 kJ

17.1kJ

1.7 kJ

28.5 kJ

85. 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

86. 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

150 kJ

300 kJ

100 kJ

50 kJ

87. An endothermic reaction is one in which

Heat is evolved

Heat is absorbed

Heat is converted into mechanical work

Heat is converted into electricity

88. 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

-27 KJ/mole

190 KJ/mole

395 KJ/mole

386 KJ/mole

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

Mechanics

Thermochemistry

Chemical kinetics

Thermodynamics

90. 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)

32 days

15 days

20 days

50 days

91. The enthalpy of formation of carbon monoxide will be

2x – y

Y – 2x/2

2x – y/2

Y – 2x

92. The reaction is spontaneous if the cell potential is

Negative

Infinite

Positive

Zero

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

Vibrational motion

Rotational motion

Translational motion

The sum of all motions which are possible

94. 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

Spontaneous

Irreversible

Non-spontaneous

Reversible

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

Coal and air react giving a reversible reaction

None of these

Burning of coal in air releases large amount of energy

Burning of coal is and endothermic process

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

Bond length

Bond strength

Bond energy

None of these

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

It is irreversible

None of these

It is reversible

It is not irreversible

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

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

Increase of free energy

Increase of enthalpy

Decrease of free energy

Decrease of entropy

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

Be double

Not change

None of these

Be half

Page 5 of 5

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

The lattice energy of the crystalline substances can be calculated easily

The energy change in a cyclic process is not zero

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

Born Haber cycle is different from Hess’s law

102. Evaporation of water is

An endothermic change

A process where no heat changes occur

A process accompanied by chemical reaction

An exothermic change

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

Exothermic

Spontaneous

Non-spontaneous

Endothermic

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

Exothermic

Photochemical

Explosive

Endothermic

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

Water equivalent

Specific heat

None of these

Thermal capacity

106. If internal energy of a system is increased

All

Temperature of the system may rise

Change in state of system can occur

Chemical reaction can take place

107. Hess’s law deals with

Changes in heat or reaction

Rate of reaction

Equilibrium constant

Influence of pressure on volume of a gas

108. Total energy of a system is

P.E + heat energy

K.E + heat energy

P.E + mechanical energy

P.E + K.E

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Mustansar KhanLast Updated: October 14, 2025

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Thermo Chemistry Practice Test Online With Explanation

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