CHEMICAL THERMODYNAMICS – 1

1) The heat of formation of an explosive compound like NCl3 is
a) Positive
b) Negative
c) Zero
d) Positive or negative

2) Lithium is the best reducing agent due to
a) Low ionisation energy
b) Small ionic radius
c) Low heat of sublimation
d) High enthalpy of hydration

3) Which of the following correctly represents the II ionisation energy of Ca?
a)
b)
c)
d)

4) The addition of the 2nd electron to a neutral atom is always a/an
a) Endothermic process
b) Exothermic process
c) Reversible process
d) None of these

5) The first ionisation potential of Na, Mg, Al, and Si is in the order
a) Si>Al> Mg>Na
b) Si>Mg> Al>Na
c) Na>Mg>Al>Si
d) Na>Mg>Al>Si

6) Arrange in the increasing order of their basic nature.
a)
b)
c)
d)

7) Which of the following statements is not correct?
a) Ionisation energies are always endothermic
b) Ionisation energy is inversely related to reducing nature
c) Electron affinity is directly related to oxidising power
d) All are correct.

8) With the help of the electronegativity table, it is possible to predict the nature of bond formed between two
a) Ions
b) Molecules
c) Atoms
d) Radicals

9) Maximum energy is evolved in which of the following processes?
a)
b)
c) F,O2-,N3-
d) K+,Ne,Ca2+

10) In which of the following is energy absorbed?
a)
b)
c) O —> O2-
d)

11) Which of the following processes requires the greatest amount of energy?
a)
b)
c)
d)

12) Which of the following transitions involves the maximum amount of energy?
a)
b)
c)
d)

13) Which of the following has the lowest ionisation potential?
a)
b)
c)
d)

14) The successive ionisation energies of an element (M) are 176, 346, and 1850 kcals. The formula of its chloride is
a) MCl
b)
c)
d)

15) Which of the following involves the greatest amount of energy?
a)
b)
c)
d)

16) Electron affinity depends to some extent upon the type of orbital that the added electron enters. It follows the order
a) s>p>d>f
b) s<p<d<f< font=””>
c) s>d>p>f
d) s<d<p<f< font=””>

17) Accordiing to Pauling, if a Bond A-B is 50% ionic, the difference in electronegativities of A and B will be:
a) 0.9
b) 1.9
c) greater than 0.9
d) Less than 1.9

18) The change in internal energy of a system depends on
a) the initial and final states of the system
b) Whether the path is reversible
c) Whether the path is irreversible
d) None of these

19) The internal energy of an ideal gas depends only upon the
a) Volume
b) Temperature
c) Pressure
d) Density

20) In an isothermal reversible cyclic process, the total change in internal energy
a) Is always positive
b) Is always negative
c) Is always zero
d) Can have any value

21) The internal energy of one mole of a gas is
a)
b)
c)
d)

22) One litre – atmosphere is approximately equal to
a) 19.2 J
b) 101 J
c) 8.31 J
d) 831 J

23) The absolute value of the internal energy of a substance cannot be determined because
a) No suitable apparatus is available
b) It has very low value
c) The individual molecules are very small in size
d) It is the sum of many quantities, some of which cannot be determined

24) The heat content of a system is the same thing as its
a) Free energy
b) Internal energy
c) Enthalpy
d) Chemical potential

25) In the reaction C(s) + O2(g) ® CO2(g) + 93.4 Kcal
a) the enthalpy of the products is greater than that of the reactants
b) the enthalpy of the products is less than that of the reactants
c) the enthalpy of the products is same as that of the reactants
d) the enthalpy of the products is half of that of the reactants

26) During the evaporation of a liquid
a) The enthalpy decreases
b) The enthalpy increases
c) The enthalpy remains unchanged
d) The internal energy decreases

27) Which of the following relationships is correct?
a) H = E -PV
b) H = E + P + V
c) H = E + PV
d) H = -E + PV

28) The correct relationship between DH and DE is
a)
b)
c)
d)

29) The enthalpies of all elements in their standard states (at 298 K,1 atm) are
a) Unity
b) Zero
c) Different
d) Negative

30) In which one of the following cases are D H and DE not equal to each other?
a) The reaction involves no gaseous reactant or product
b) The number of moles of gaseous reactants and gaseous products is not equal to each other
c) The number of moles of gaseous reactants and gaseous products is equal to each other
d) The process is carried out in a closed vessel

31) Internal energy does not include
a) Vibration energy
b) Rotational energy
c) Energy arising by gravitational pull
d) Nuclear energy

32) When a solid melts there is
a) An increase in enthalpy
b) A decrease in enthalpy
c) No change in enthalpy
d) A decrease in internal energy

33) D E is the heat absorbed at constant
a) Temperature(T)
b) Pressure(P)
c) Volume(V)
d) T,P and V

34) An exothermic reaction is one which
a) Takes place on heating
b) Is accompanied by a flame
c) Is accompanied by the absorption of heat
d) Is accompanied by the evolution of heat

35) In an exothermic reaction, the enthalpy of reaction is
a) Positive
b) Negative
c) Zero
d) Any one of these

36) In an exothermic reaction
a)
b)
c)
d) None

37) Which of the following reaction do you think will result in the absorption of heat?
a) Carbon burning in air
b) Iron reacting with sulphur to form iron sulphide
c) Formation of water gas from steam and coke
d) Formation of producer gas

38) When ammonium chloride is dissolved in water, the solution becomes cold. The change is
a) Endothermic
b) Exothermic
c) Super cooling
d) None of the above

39) An endothermic reaction is allowed to take place rapidly in air. The temperature of the surrounding air
a) Increases
b) Decreases
c) Remains same
d) Cannot be predicted

40) In an endothermic reaction, the energy of the products
a) Is less than that of the reactants
b) Is greater than that of the reactants
c) Is same as that of the reactants
d) Is zero

41) The formation of water from H 2 (g) and O2(g) is an exothermic reaction because
a)
b)
c)
d) Energy considerations do not arise

42) Of the reactions stated, the one which is endothermic is the
a) Burning of sulphur to form sulphur dioxide
b) Conversion of monoclinic sulphur to rhombic sulphur
c) Formation of carbon dioxide from carbon and oxygen
d) Melting of sulphur

43) Look at the following diagram:
The enthalpy change for the reaction A® B will be


a) -25 kJ
b) -40 kJ
c) +25 kJ
d) -65 kJ

44) The factor which does not affect the heat of reaction is
a) the physical state of the reactants and products
b) The temperature of the reaction
c) Whether the reaction is carried out in an open vessel or a closed vessel
d) Whether the reaction is carried out directly or indirectly

45) Which one of the following expresses Q as the heat of combustion?
a)
b)
c)
d)

46) The standard state in chemical energetics implies
a) 283K
b) 1 atmospheric pressure
c) 273 K,1 atm pressure
d) 298 K,1 atm pressure

47) Which one of the following expresses the heat of formation of CO2?
a)
b)
c)
d)

48) The heat of combustion of a fuel is called its
a) Enthalpy
b) Internal energy
c) Calorific value
d) None of these

49) In a chemical reaction, the heat of formation is the heat
a) Evolved
b) Absorbed
c) Evolved or absorbed
d) Zero

50) For which of the following is DH always negative ?
a) Heat of formation
b) Heat of neutralization
c) Heat of solution
d) Heat of fusion

51) The standard heat of formation of diamond is
a) Same as that of graphite
b) Greater that that of graphite
c) Less than that of graphite
d) Taken as zero

52) In which one of the following cases is the heat of neutralization minimum?
a)
b)
c)
d)

53) The heat of neutralization of a strong acid by a strong base
a) Depends upon the nature of the acid
b) Depends upon the nature of the base
c) Depends upon the nature of both acid and the base
d) Is always constant

54) The enthalpy of reaction at constant volume(D E) is related to the enthalpy of reaction at constant pressure(D H) as
a)
b)
c)
d) None of these is correct

55) When 1 mole of H2O2 is decomposed by platinum black, the heat evolved is 96.6 kJ. The heat of formation of 1 mole of H2O2 is
a) 96.6 kJ
b) 193.2 kJ
c) 386.4 kJ
d) -96.6 kJ

56) The heats of combustion of hydrogen, carbon monoxide and methane are –285kJmol-1, -284 kJmol-1 and  –890 kJmol-1respectively. The calorific value is maximum for
a)
b) CO
c)
d) Cannot be predicted as information is incomplete

57) For which one of the following elements is the standard enthalpy not zero?
a) C(Diamond)
b) C(Graphite)
c) Liquid mercury
d) Rhombic sulphur

58) If the heat of solution for one mole of KCl in 20 moles of water and 200 moles of water are +3.80 k cal and +4.40 kcal respectively, then the heat of dilution is
a) +8.20 kcal
b) – 8.2 kcal
c) +0.60 kcal
d) – 0.60 kcal

59) 1 mole of H2SO4 is mixed with 2 moles of NaOH. The heat evolved will be
a) 57.3 kJ
b)
c) 57.3 / 2 kJ
d) cannot be predicted

60) The heat of combustion of solid benzoic acid at constant volume is –321.30 kJ at 270C.The heat of combustion at constant pressure is
a) -321.30 – 300 R
b) -321.30 + 300 R
c) -321.30 – 150 R
d) -321.30 + 900 R

61) The heat of formation of H2O(l) is – 68.0 kcal; the heat of formation of H2O(g) is likely to be
a) – 68.0 kcal
b) – 69.4 kcal
c) 80.0 kcal
d) – 58.3 kcal

62) The heat of formation, DH0f of an explosive compound like NCl3 is
a) Positive
b) Negative
c) Zero
d) Positive or negative

63) The heats of neutralisation of four acids a, b, c, and d when neutralised against a common base are 13.7, 9.4, 11.2 and 12.4 kcal respectively. The weakest among these acids is
a) a
b) b
c) c
d) d

64) An ideal gas is allowed to expand under adiabatic conditions. What is zero for such a process?
a)
b)
c)
d) None of these

65) The equation giving the variation of heat of a reaction with temperature is known as
a)
b)
c)
d)

66) The heat of combustion of a reaction does not depend on the
a) Physical state of the substance
b) Temperature at which combustion is carried out
c) Amount of oxygen present
d) Whether the combustion is carried out in an open vessel or a closed vessel

67) In the reaction CuSO4(s) + 5H2O(l) ® CuSO4.5H2O(s); DH = -x kJ ,    DH represents the
a) Enthalpy of dilution
b) Enthalpy of solution
c) Enthalpy of hydration
d) All the above

68) According to Hess’s law, the enthalpy change during a chemical reaction depends upon
a) The path by which the reactants change into products
b) The temperature of the reactants and the products
c) The nature of the initial reactants and the final products
d) The volume change accompanying the chemical reaction

69) Hess’s law deals with the
a) Changes in the heat of reaction
b) Rate of reaction
c) Equilibrium constant
d) Influence of pressure on volume of a gas

70) Hess’s law of constant heat summation is based on
a)
b) Conversion of mass
c) the first law of thermodynamics
d) None of the above

71) A hypothetical reaction, A® 2 B, proceeds through following sequence of steps
(i) A ® C; DH = q1
(ii) C ® D; D H = q2
(iii) 1/2 D ® B; DH = q3
The heat of reaction is

a)
b)
c)
d)

72) RRR The signs of DG for the process of melting of ice at 273 K and 1atm pressure is
a) Positive
b) Negative
c) Neither positive nor negative
d) Either positive or negative

73) A system which can exchange energy but no matter with the surroundings is called
a) A heterogeneous system
b) An open system
c) A closed system
d) An isolated system

74) An intensive property in thermodynamics means a property which depends
a) On the amount of the substance only
b) On the nature of the substance only
c) Both on the amount as well as the nature of the substance
d) Neither on the amount nor on the nature

75) Which of the following statements is correct?
a) Internal energy is a state function but work is not
b) Work is a state function but internal energy is not
c) Both internal energy and work are state function
d) Neither internal energy nor work is a state function

76) During the isothermal expansion of an ideal gas, its internal energy
a) Decreases
b) Increases
c) May increase or decrease
d) Remains unchanged

77) In which one of the following sets do all the properties belong to the same category (all extensive or all intensive)?
a) Mass, volume, pressure
b) Temperature, pressure, volume
c) Heat capacity, density , entropy
d) Enthalpy, internal energy, volume

78) A process in which no heat change takes place is called
a) An isothermal process
b) An adiabatic process
c) An isobaric process
d) An isochoric process

79) Which one is true?
a) 1 calorie > 1 erg > 1 Joule
b) 1 erg > 1 calorie > 1 Joule
c) 1 calorie > 1 Joule > 1 erg
d) 1 Joule > 1 calorie > 1 erg

80) A thermodynamic state function is
a) One which obeys all the laws of thermodynamics
b) A quantity which is used to measure thermal change
c) A quantity whose value is independent of the path
d) A quantity which is used to express pressure – volume work

81) Which among the following is not a state function?
a) Internal energy
b) Free energy
c) Work
d) Enthalpy

82) When a gas is subjected to adiabatic expansion, it gets cooled due to the
a) Fall in temperature
b) Loss in kinetic energy
c) Decrease in velocity
d) energy spent in doing work

83) Which among the following is an extensive property of the system?
a) Temperature
b) Volume
c) Refractive index
d) Viscosity

84) A gas expands isothermally and reversibly. The work done by the gas is
a) Zero
b) Maximum
c) Minimum
d) Cannot be determined

85) A spontaneous process is defined as a process which
a) Takes place instantaneously
b) Takes place by itself but not try initiation
c) Needs some initiation like heat, electricity etc
d) Takes place by itself or by initiation

86) Which one of the following processes is non- spontaneous?
a) the burning of coal
b) Flow of heat from a hot end to a cold end
c) Lifting of water by an electric pump into a reservoir at the top of a building
d) the reaction between hydrogen and oxygen to form water

87) For a reversible isothermal process in equilibrium, the entropy change is given by the expression
a)
b)
c)
d)

88) An equilibrium mixture of ice and water is held at constant pressure. On heating some ice melts. For the system
a) the free energy increases
b) the entropy increases
c) the enthalpy decreases
d) the entropy decreases

89) The entropy change of a system and its surroundings in equilibrium
a) Increases
b) Decreases
c) Remains constant
d) Either increases or decreases

90) For the reaction 2 SO2(g) + O2(g) ® 2 SO3(g) , the entropy
a) Increases
b) Decreases
c) Remains unchanged
d) Change cannot be predicted

91) A reaction has both DH and D S negative. The reaction is
a) Spontaneous at all temperatures
b) Spontaneous at low temperatures and non spontaneous at high temperatures.
c) Non-spontaneous at all temperatures.
d) Spontaneous at high temperatures and non spontaneous at low temperatures

92) For an exothermic reaction to be spontaneous at all temperatures,
a)
b)
c)
d)

93) The approximate enthalpy of fusion of ice and the enthalpy of vaporisation of water per mole respectively are
a) 18 kJ, 80 kJ
b) 6 kJ, 40.6 kJ
c) 80 kJ, 540 kJ
d) 8 kJ, 80 kJ

94) DS = DH / T holds good for
a) an adiabatic process
b) an isothermal reversible phase change
c) A process at constant pressure
d) A process under any conditions

95) In a reversible process , DS sys + DS surr is
a) >0
b) < 0
c)
d) = 0

96) The total entropy change of a system and its surroundings is positive for
a) a reversible process
b) an irreversible process
c) an isochoric process
d) an isobaric process

97) The free energy change of a reversible reaction at equilibrium is
a) Infinite
b) Zero
c) Positive
d) Negative

98) Which of the following expressions defines the physical significance of free energy change?
a)
b)
c)
d)

99) Which one of the following is correct?
a)
b)
c)
d)

100) Which of the following describes the criterion of spontaneity?
a)
b)
c)
d) All of these


Answer :

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