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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
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Thermo Chemistry Practice Test Online With Explanation

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Page 1 of 5

Chemistry

1. Calorie is equivalent to

418.4 J

4.184 J

41.84 J

0.4184 J

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

Remains constant

Decreases

Remains same

Increases

3. In endothermic reactions, the heat content of the

Reactants and products are equal

Products is more than that of reactants

Both a and b

Reactants is more than that of products

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

Chemical process

Physical process

Endothermic process

Biochemical process

5. Most of the reactions which give stable products are

Isothermal

Exothermic

None of these

Endothermic

6. 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

11.46 kJ

573 kJ

7. Evaporation of water is

A process where no heat changes occur

An exothermic change

A process accompanied by chemical reaction

An endothermic change

8. An endothermic reaction is one in which

Heat is converted into mechanical work

Heat is evolved

Heat is converted into electricity

Heat is absorbed

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

15 days

50 days

20 days

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

Enthalpy of reaction

Heat of neutralization

Heat of combustion

Hat of formation

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

Photochemical

Endothermic

Exothermic

Explosive

12. In general, for exothermic reactions to be spontaneous

Temperature should be low

Temperature has no effect

Temperature should be zero

Temperature should be high

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

Thermodynamics

Chemical kinetics

Thermochemistry

Mechanics

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

∆H = ∆E + d

∆H = ∆E – PV

∆H = ∆E – d

∆H = ∆E + Pv

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

Surrounding

System

Any substance

State function

16. When a bond breaks

Temperature increases

Heat is absorbed

Heat is evolved

No change in heat contents takes place

17. All of the following are state function except

18. 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

HCl is more stable than HF

HF and HCl are endothermic compounds

HF is more stable than HCl

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

Vibrational motion

Translational motion

Rotational motion

The sum of all motions which are possible

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

None of these

It is reversible

It is not irreversible

It is irreversible

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

4 kg H₂O

1 kg H₂O

3 kg H₂O

2 kg H₂O

22. If internal energy of the system is increased

Change in state of the system is increased

Temperature of the system may rise

All

Chemical reaction may take place

23. Total energy of a system is

P.E, + mechanical energy

P.E. + heat energy

K.E, + heat energy

P.E, + K.E.

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

+64.8 kcal mol¯¹

+21.4 kcal mol¯¹

-231.6 kcal mol¯¹

-94.0 kcal mol¯¹

25. 1 mole of H₂SO₄ is mixed with 2 mole of NaOH. The heat evolved will be

57.3/2 kJ

2 x 57.3 kJ

Cannot be predicted

57.3 kJ

Page 2 of 5

26. If internal energy of a system is increased

All

Change in state of system can occur

Chemical reaction can take place

Temperature of the system may rise

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

Thermal decomposition

Neutralization

Respiration

Combustion

28. Pumping of water uphill is

Irreversible process

Non spontaneous

Spontaneous process

None of these

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

Synthesis

Endothermic

Both a and b

Exothermic

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

Calorie

Electron – volt

Erg

Joule

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

State function

Energy of the system

Chemical property

Physical property

32. 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 sublime

Ice will melt

Water will freeze

Water will vaporize

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

Pressure

Volume

Density

Temperature

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

Exothermic

Both a and b

Decomposition

Endothermic

35. The reaction is spontaneous if the cell potential is

Infinite

Negative

Zero

Positive

36. Reaction in which heat is evolved

Spontaneous

Endothermic

Exothermic

Non-spontaneous

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

Isothermal

Isolated

Adiabatic

Closed

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

39. 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

1.2 K

2.4 K

6.6 K

4.8 K

40. Which one is not a state function?

Work

Enthalpy

Internal energy

Gibbs free energy

41. The enthalpy of formation of carbon monoxide will be

Y – 2x

2x – y/2

2x – y

Y – 2x/2

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

Spontaneous

Non-spontaneous

Endothermic

Exothermic

43. Two fundamental ways to transfer energy are

Heat and volume

Pressure and temperature

Pressure and volume

Heat and work

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

Entropy change

Enthalpy change

Internal energy change

Free energy change

45. Total energy depends upon the state of system

Free energy of reaction

Enthalpy

Entropy of reaction

All above

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

∆H = ∆E + P∆V

∆E = q + w

Q = m x X x ∆ T

P∆V + nRT

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

Graphite has more energy than diamond

Stability cannot to predicated

Graphite is more stable than diamond

Both are equally stable

48. An adiabatic expansion of an ideal gas always has

W = 0

Decrease in temperature

Q = 0

∆H = 0

49. 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

0.1 R

2.303 R

50. 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

-668 kJ mol¯¹

668 kJ mol¯¹

-112 kJ mol¯¹

112 kJ mol¯¹

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51. A spontaneous change means

A lowering of free energy

No energy change

An increase in internal energy

A lowering of energy

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

110.5 kJ

676.5 kJ

53. Unit of heat is SI system is

Cal

KCaL

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

Be double

Be half

Not change

None of these

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

Photochemistry

Thermochemistry

Kinetics

Thermodynamics

56. 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 218 kcal of energy

Release of 109 kcal of energy

Unpredictable

Absorption of 218 kcal of energy

57. Endothermic changes are indicated through

All of these

Making of chemical bond

Burning of carbon

Breaking of chemical bonds

58. 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

11.272 JK¯¹

9.75 JK¯¹

2.33 JK¯¹

Insufficient data

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

-250 kJ

+250 kJ

+125 kJ

-125 kJ

60. 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?

Zero

< 40 kJ

> 40 kJ

40 kJ

61. 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

= - k719

= + k319

-400J

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

Unity

Negative

Positive

Zero

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

Erg

Electron – volt

Calorie

Joule

64. 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

-523.3 kJ mol¯¹

-339.3 kJ mol¯¹

-221.1 kJ mol¯¹

65. The law of Lavoisier and Laplace illustrates

Equivalent of mechanical and chemical energy

The principle of conservation of matter

Equivalence of mechanical and thermal energy

The principle of conservation of energy

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

Joule cm¯¹ deg¯¹

Joule deg¯¹ Kg¯¹

Joule deg¯¹ atom¯¹

Joule deg¯¹ mol¯¹

67. 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

71030 calories

-70 calories

70960 calories

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

Charles’s law

Henry’s law

Graham’s law

Hess’s law

69. 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

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

Exothermic

Spontaneous

Endothermic

Non-spontaneous

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

Energy and volume

Temperature and pressure

Temperature and volume

Pressure and volume

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

Calorie

Watt

None of these

Joules

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

Zeroth law

First law

Third law

Second law

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

Glass Calorimeter

Monometer

Thermometer

Bomb Calorimeter

75. Two fundamental ways to transfer energy are

Pressure and temperature

Heat and volume

Heat and work

Pressure and volume

Page 4 of 5

76. 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

21.98

20.13

2.198

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

Have the same energy as the products

Have less energy than the products

Have more energy than the products

Are at a higher temperature than the products

78. 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

79. 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

45.7 kJ

1.7 kJ

17.1kJ

80. Total energy of a system is

P.E + mechanical energy

P.E + K.E

K.E + heat energy

P.E + heat energy

81. Which statement describes characteristics of an endothermic reaction?

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

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

82. Hess’s law deals with

Equilibrium constant

Changes in heat or reaction

Influence of pressure on volume of a gas

Rate of reaction

83. Which type of reactions cannot occur spontaneously?

Neither

Exothermic

Both a and b

Endothermic

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

Bond length

Bond strength

Bond energy

None of these

85. 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

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

Surrounding

State

System

Phase

87. 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 is and endothermic process

Burning of coal in air releases large amount of energy

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

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

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

89. 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

90. Which of the following is not correct?

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

Dissolution on NH₄Cl in excess of water is an endothermic process

Neutralization is always exothermic

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

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

Calorie

Electron vol

Erg

Joule

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

Kinetics

Thermodynamics

Stoichiometry

Thermochemistry

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

Glass calorimeter

Bomb calorimeter

Copper calorimeter

All above

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

Irreversible

Non-spontaneous

Spontaneous

Reversible

95. 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

96. For a reaction to occur spontaneously

∆ H must be zero

∆ H must be negative

∆ H must be positive

∆ H must be unity

97. Unit of heat in S.I system is

Cal

Kcal

98. 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

-22 kcal

-11 kcal

-44 kcal

-88 kcal

99. Which one is not state function?

Enthalpy

Work

Gibbs free energy

Internal energy

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

Graham’s law

Henry’s law

Boyle’s law

Hess’s law

Page 5 of 5

101. 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

102. 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

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

None of these

Water equivalent

Thermal capacity

Specific heat

104. Most of the thermodynamic parameters are

Phase

Surrounding

State function

System

105. Enthalpy of a reaction can be measured by

Glass calorimeter

Thermometer

Manometer

Barometer

106. Mechanical work is especially important in systems that contain

Solid-solid

Solid-liquid

Liquid-liquid

Gases

107. Free energy change for a reversible process is:

Equal to zero

Unpredictable

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

386 KJ/mole

-27 KJ/mole

395 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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