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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. Total energy depends upon the state of system

Enthalpy

Entropy of reaction

All above

Free energy of reaction

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

Adiabatic

Isothermal

Isolated

Closed

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

Bomb calorimeter

Copper calorimeter

Glass calorimeter

All above

4. 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

-88 kcal

-44 kcal

-11 kcal

-22 kcal

5. Mechanical work is especially important in systems that contain

Solid-solid

Gases

Liquid-liquid

Solid-liquid

6. If internal energy of the system is increased

Change in state of the system is increased

All

Chemical reaction may take place

Temperature of the system may rise

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

Charles’s law

Hess’s law

Henry’s law

Graham’s law

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

Endothermic

Photochemical

Exothermic

Explosive

9. 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

50 days

15 days

20 days

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

Biochemical process

Physical process

Chemical process

Endothermic process

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

Temperature

Volume

Density

Pressure

12. 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)

2.198

21.98

20.13

2.013

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

14. An adiabatic expansion of an ideal gas always has

W = 0

Decrease in temperature

∆H = 0

Q = 0

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

None of these

Calorie

Watt

Joules

16. A spontaneous change means

A lowering of energy

An increase in internal energy

A lowering of free energy

No energy change

17. 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

18. Endothermic changes are indicated through

All of these

Burning of carbon

Breaking of chemical bonds

Making of chemical bond

19. Total energy of a system is

P.E + mechanical energy

K.E + heat energy

P.E + K.E

P.E + heat energy

20. 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

Work done is independent of its path

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

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

21. 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

= - k719

0 J

= + k319

-400J

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

None of these

It is not irreversible

It is reversible

It is irreversible

23. Most of the thermodynamic parameters are

State function

Surrounding

Phase

System

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

Remains constant

Remains same

Increases

Decreases

25. Most of the reactions which give stable products are

Exothermic

Endothermic

Isothermal

None of these

Page 2 of 5

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

100.0 R

10.0 R

2.303 R

0.1 R

27. When a bond breaks

No change in heat contents takes place

Temperature increases

Heat is absorbed

Heat is evolved

28. Which of the following is not correct?

Dissolution on NH₄Cl in excess of water is an endothermic process

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

Neutralization is always exothermic

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

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

Exothermic

Decomposition

Endothermic

Both a and b

30. Unit of heat in S.I system is

Kcal

Cal

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

Bond strength

Bond length

Bond energy

None of these

32. 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 is more stable than HCl

HF and HCl are endothermic compounds

HCl is more stable than HF

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

Chemical property

Energy of the system

Physical property

State function

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

P∆V + nRT

Q = m x X x ∆ T

∆E = q + w

∆H = ∆E + P∆V

35. 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

50 kJ

300 kJ

100 kJ

36. Free energy change for a reversible process is:

Unpredictable

Equal to zero

37. 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

Heat of combustion

Enthalpy of reaction

38. 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

39. Calorie is equivalent to

4.184 J

0.4184 J

418.4 J

41.84 J

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

Stoichiometry

Thermochemistry

Thermodynamics

Kinetics

41. 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

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

Energy and volume

Temperature and pressure

Temperature and volume

Pressure and volume

43. 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

Release of 218 kcal of energy

Absorption of 218 kcal of energy

Release of 109 kcal of energy

44. Enthalpy of a reaction can be measured by

Barometer

Manometer

Thermometer

Glass calorimeter

45. 1 mole of H₂SO₄ is mixed with 2 mole of NaOH. The heat evolved will be

2 x 57.3 kJ

57.3/2 kJ

57.3 kJ

Cannot be predicted

46. 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

-523.3 kJ mol¯¹

-439.3 kJ mol¯¹

-221.1 kJ mol¯¹

-339.3 kJ mol¯¹

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

∆H = ∆E – PV

∆H = ∆E + Pv

∆H = ∆E – d

∆H = ∆E + d

48. 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

Non-spontaneous

Irreversible

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

Both are equally stable

Stability cannot to predicated

Graphite is more stable than diamond

Graphite has more energy than diamond

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

Decrease of entropy

Increase of free energy

Increase of enthalpy

Decrease of free energy

Page 3 of 5

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

Are at a higher temperature than the products

Have more energy than the products

Have less energy than the products

Have the same energy as the products

52. 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)

28.5 kJ

1.7 kJ

17.1kJ

45.7 kJ

53. 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

> 40 kJ

Zero

40 kJ

54. 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

Insufficient data

2.33 JK¯¹

9.75 JK¯¹

11.272 JK¯¹

55. Which one is not a state function?

Work

Gibbs free energy

Enthalpy

Internal energy

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

Spontaneous

Exothermic

Non-spontaneous

Endothermic

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

Specific heat

Thermal capacity

None of these

Water equivalent

58. Which one is not state function?

Enthalpy

Work

Internal energy

Gibbs free energy

59. The law of Lavoisier and Laplace illustrates

Equivalence of mechanical and thermal energy

The principle of conservation of matter

Equivalent of mechanical and chemical energy

The principle of conservation of energy

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

Chemical kinetics

Mechanics

Thermochemistry

Thermodynamics

61. For a reaction to occur spontaneously

∆ H must be unity

∆ H must be positive

∆ H must be zero

∆ H must be negative

62. An endothermic reaction is one in which

Heat is evolved

Heat is converted into electricity

Heat is converted into mechanical work

Heat is absorbed

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

State

Surrounding

System

Phase

64. Hess’s law deals with

Equilibrium constant

Influence of pressure on volume of a gas

Changes in heat or reaction

Rate of reaction

65. 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 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 negative, and the products have less potential energy than the reactants

66. Unit of heat is SI system is

Cal

KCaL

67. In general, for exothermic reactions to be spontaneous

Temperature should be low

Temperature should be zero

Temperature has no effect

Temperature should be high

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

State function

System

Surrounding

Any substance

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

Calorie

Electron – volt

Erg

Joule

70. 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

-70 calories

+70 calories

71030 calories

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

Born Haber cycle is different from Hess’s law

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

The lattice energy of the crystalline substances can be calculated easily

The energy change in a cyclic process is not zero

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

Second law

Third law

First law

Zeroth law

73. Reaction in which heat is evolved

Endothermic

Spontaneous

Exothermic

Non-spontaneous

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

Thermal decomposition

Neutralization

Respiration

Combustion

75. Two fundamental ways to transfer energy are

Heat and volume

Heat and work

Pressure and temperature

Pressure and volume

Page 4 of 5

76. 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

77. All of the following are state function except

78. Two fundamental ways to transfer energy are

Heat and volume

Pressure and temperature

Pressure and volume

Heat and work

79. 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

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

Hess’s law

Boyle’s law

Henry’s law

Graham’s law

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

Non-spontaneous

Spontaneous

Endothermic

Exothermic

82. 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

Ice will melt

Water will freeze

Water will vaporize

Ice will sublime

83. The enthalpy of formation of carbon monoxide will be

2x – y

2x – y/2

Y – 2x/2

Y – 2x

84. 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

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

Free energy change

Enthalpy change

Entropy change

Internal energy change

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

Positive

Unity

Zero

Negative

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

Erg

Joule

Calorie

Electron – volt

88. 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 is and endothermic process

Burning of coal in air releases large amount of energy

Coal and air react giving a reversible reaction

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

Thermometer

Bomb Calorimeter

Monometer

Glass Calorimeter

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

Be half

None of these

Not change

Be double

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

Exothermic

Both a and b

Synthesis

Endothermic

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

Joule

Calorie

Erg

Electron vol

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

Photochemistry

Thermodynamics

Thermochemistry

Kinetics

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

Heat of neutralization

Heat of reaction

Heat of sublimation

Heat of combustion

95. Which type of reactions cannot occur spontaneously?

Neither

Endothermic

Exothermic

Both a and b

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

+142.5 kJ

+285 kJ

-285 kJ

-142.5 kJ

97. Evaporation of water is

An endothermic change

A process where no heat changes occur

An exothermic change

A process accompanied by chemical reaction

98. 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

2.4 K

6.6 K

1.2 K

4.8 K

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

1 kg H₂O

3 kg H₂O

4 kg H₂O

2 kg H₂O

100. If internal energy of a system is increased

Chemical reaction can take place

Temperature of the system may rise

All

Change in state of system can occur

Page 5 of 5

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

+64.8 kcal mol¯¹

-94.0 kcal mol¯¹

+21.4 kcal mol¯¹

-231.6 kcal mol¯¹

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

573 J

57.3 kJ

573 kJ

11.46 kJ

103. 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

-676.5 kJ

-110.5 kJ

676.5 kJ

110.5 kJ

104. Pumping of water uphill is

Spontaneous process

Non spontaneous

Irreversible process

None of these

105. Total energy of a system is

K.E, + heat energy

P.E, + mechanical energy

P.E. + heat energy

P.E, + K.E.

106. 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 a + ve value for the entropy change and a – ve value for the enthalpy change

It has small + ve value for enthalpy change

It has a large – ve value for the entropy change

107. The reaction is spontaneous if the cell potential is

Negative

Infinite

Zero

Positive

108. 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

190 KJ/mole

395 KJ/mole

386 KJ/mole

-27 KJ/mole

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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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