CHEMICAL THERMODYNAMICS – 2

1) For the precipitation reaction of Ag+ ions with NaCl, which of the following statements is correct ?
a)
b)
c)
d)

2) The sign 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

3) Which name is not associated with thermodynamics?
a) Claussius
b) Helmholtz
c) Carnot
d) Ohm

4) ” If a system A is in thermal equilibrium with B and B is in thermal equilibrium with C, then A and C are in equilibrium with each other”. This is a statement of
a) Cyclic rule
b) the zero law of thermodynamics
c) First law of thermodynamics
d) Second law of thermodynamics

5) The first law of thermodynamics states that
a) The internal energy of a system is constant
b) The enthalpy of a system is constant
c) There is an equivalence between mass and energy
d) Energy can neither be created nor be destroyed

6) According to the latest sign conventions, the correct expression representing the first law of thermodynamics is
a)
b)
c)
d) All the expressions are correct

7) Which law of thermodynamics introduces the concept of entropy?
a) First law
b) Zero law
c) Third law
d) Second law

8) In any natural process
a) The entropy of universe remains constant
b) The entropy of the universe tends towards a maximum
c) The entropy of the universe tends towards a minimum
d) Any of the above can happen

9) The maximum efficiency of a stem engine operating between 1000C and 250C is
a) 20 %
b) 22.2 %
c) 25 %
d) 30 %

10) @ Calculate the temperature at which G = -5.2 kJ mol-1, H = 145.6 kJ mol-1 and S = 216 JK-1 mol-1 for a chemical reaction.
a)
b)
c)
d)

11) Which law of thermodynamics helps in calculating the absolute entropies of various substances at different temperatures?
a) 1st law
b) 2nd law
c) 3rd law
d) Zeroth law

12) According to the third law of thermodynamics, the entropy at 0 0K is zero for
a) elements in their stable form
b) perfectly crystalline solids
c)
d) gaseous substances only

13) DG for the reaction Ag2O ® 2 Ag + ½ O2 at a certain temperature is
found to be –10.0 kJ mol –1.Which one of the following statements is correct at this temperature?
a) Silver oxide decomposes to give silver and oxygen
b) Silver and oxygen combine to form silver oxide
c) The reaction is in equilibrium
d) The reaction can neither occur in the forward direction nor in the backward direction

14) Which of the following statements is correct?
a)
b)
c) The heat of neutralisation of strong acids with strong bases is ndependent of the identity of the acid and base
d) The enthalpy of fusion is negative

15) The heat required to decompose a compound into its elements is equal to the heat evolved when the compound is formed from its elements. This is in accordance with
a) Hess’s law
b) the first law of thermodynamics
c) Joule – Thomson law
d)

16) In a change from state A to state B
a) q depends only on the initial and final state
b) w depends only on the initial and final state
c)
d)

17) A monoatomic helium molecule possesses
a) Only potential energy
b) Potential as well as vibrational energy
c) Vibrational as well as translational energy
d) Translational as well as potential energy

18) Vibrational energy is
a) Partially potential and partially kinetic
b) Only potential
c) Only kinetic
d) None of the above

19) If a refrigerator’s door is kept open, then overall
a) the room will be cooled
b) the room will be heated
c) the room may get cooled or heated depending upon the weather
d) there will not be any effect on the room

20) The efficiency of a heat engine is maximum when the
a) Temperature of the source is greater than that of the sink
b) Temperature of the sink is greater than that of the source
c) Temperature difference of the source and sink is minimum
d) Temperature difference of the source and sink is maximum

21) A system changes from state A(P1,V1,T1) to B(P2,V2,T2) to C(P3,V3,T3) and then back to A. The complete process is called a
a) Reversible process
b) Cyclic process
c) Spontaneous process
d) Isobaric process

22) Which of the following units represents the largest amount of energy?
a) Calorie
b) Joule
c) Erg
d) Electron volt

23) The energy equivalent to one erg, one joule, and one calorie in the increasing order is
a) 1 erg,1 joule,1 cal
b) 1 erg,1 cal,1 joule
c) 1 cal,1 joule,1 erg
d) 1 joule,1 cal, 1 erg

24) The heat of neutralization of a strong acid and a weak base is
a) 13.7 kcal
b) Greater than 13.7 kcal
c) Less than 13.7 kcal
d) None of the above

25) An endothermic reaction is one in which
a) Heat is converted into electricity
b) Heat is absorbed
c) Heat is evolved
d) Heat is converted into mechanical work

26) A spontaneous change is one in which the system suffers
a) An increase in internal energy
b) A lowering of entropy
c) A lowering of free energy
d) No energy change

27) A compound with a negative heat of formation is known as
a) an endothermic compound
b) an exothermic compound
c) a heat of formation compound
d) None of the above

28) The combustion of methane
a) is an exothermic reaction
b) is an endothermic reaction
c) requires a catalyst
d) yields H2

29) The latent heat of vaporisation of a liquid at 500 K and 1 atm. The pressure is 10.0 kcal / mol. What will be the change in internal energy of 3 moles of the liquid at the same temperature and pressure ?
a) 27.0 kcal
b) 13.0 kcal
c) -27.0 kcal
d) -13.0 kcal

30) For a spontaneous chemical process, the free energy change is
a) Positive
b) Negative
c) Either positive or negative
d) Zero

31) The process of evaporation of a liquid is accompanied by
a) a decrease in entropy
b) a decrease in enthalpy
c) No change in free energy
d) an increase in entropy

32) The decreasing order of calorific values is
a)
b)
c)
d)

33) For which of the following processes will energy be absorbed?
a) Separating an electron from an electron
b) Separating a proton from a proton
c) Separating a neutron from a neutron
d) Separating an electron from a neutral atom

34) When two atoms of hydrogen combine to form a molecule of hydrogen gas, the energy of the molecule is
a) Higher than that of the separate atoms
b) Equal to that of the separate atoms
c) Lower than that of the separate atoms
d) Sometimes lower and sometimes higher

35) For which reaction from the following will DS be maximum?
a)
b)
c)
d)

36) The free energy change for a reversible reaction at equilibrium is
a) Zero
b) Small positive
c) Small negative
d) Large positive

37) When water is added to conc. H2SO4 it gets very hot. This happens because the dilution of conc. H2SO4 is
a) An exothermic reaction
b) An endothermic reaction
c) Photochemical reaction
d) Hydrolytic reaction

38) The heat of transition is the heat evolved or absorbed when a substance is converted from
a) Solid to liquid
b) Solid to vapour
c) Liquid to vapour
d) One allotropic form to another allotropic form

39) Calculate the free energy change for the following reaction at 300 K. 2 CuO (s) Cu2O (s) + O2 (g). Given H = 145.6 kJ mol-1 and S = 116 JK-1 mol-1
a)
b)
c)
d)

40) DH combustion of a compound is
a) positive
b) negative
c) zero
d) positive or negative

41) The heat of neutralization of NH4OH and HCl is
a) 13.7 kcal/mole
b) < 13.7 kcal/mole
c) > 13.7 kcal/mole
d) zero

42) If C(g) + O2(g) ® CO2(g) , DH = r, and CO(g) +1/2 O2(g) ® CO2(g) ,D H = s,
Then the heat of formation of CO is

a) r + s
b) r – s
c) s – r
d) r / s

43) All naturally occurring processes proceed spontaneously in a direction which leads to the
a) decrease of entropy
b) increase of enthalpy
c) increase of free energy
d) decrease of free energy

44) The heat of neutralisation of an acid by a base is highest when
a) both the acid and base are week
b) both the acid and base are strong
c) the acid is strong and the base is weak
d) the acid is weak and the base is strong

45) Which of the following expressions expresses the first law of thermodynamics ?
a)
b)
c)
d)

46) One gram atom of graphite and one gram atom of diamond were separately burnt to carbon dioxide. The amount of heat liberated were 393.5 kJ and 395.4 kJ respectively. It follows that
a) graphite has greater affinity for oxygen
b) diamond has greater affinity for oxygen
c) graphite is more stable than diamond
d) diamond is more stable than graphite

47) A solution of 500 ml of 0.2 M KOH and 500 ml of 0.2 M HCl is mixed and stirred; the rise in temperature is T1.The experiment is repeated using 250 ml each of solution, the temperature rise is T2.Which of the following is true?
a)
b)
c)
d)

48) The conversion of oxygen to ozone represented by the equation 3O2 ® 2O3 is an endothermic reaction. The enthalpy change, DH accompanying the reaction
a) is negative
b) is positive
c) is zero
d) depends on temperature

49) Which has maximum calorific value?
a) Fat
b) Protein
c) Carbohydrate
d) Amino acid

50) The enthalpy of a reaction at 27 0 C is 15kJ mol -1. The reaction will be feasible if the entropy is
a)
b)
c)
d)

51) A reaction is non spontaneous at all temperatures if
a)
b)
c)
d)

52) For the process CO2 (s) ® CO2(g)
a)
b)
c)
d)

53) The heat of neutralisation of a strong acid and a strong base is nearly equal to
a) 10 kJ/mole
b) 10 Cal/mole
c) – 57 kJ/mole
d) – 57 Cal/mole

54) The enthalpy change for the process A (s) —> A (g) corresponds to the enthalpy of
a) fusion
b) vaporization
c) combustion
d) sublimation

55) If CH3COOH + OH ® CH3COO + H2O + q1 and H++ OH ® H2O + q2, then the enthalpy change for the reaction CH3COOH ® CH3COO+ H+ is equal to
a)
b)
c)
d)

56) The enthalpies of formation of organic substances are conveniently determined from their
a) Enthalpy of combustion
b) Boiling point
c) Melting point
d) Enthalpy of neutralisation

57) Which of the following reactions is endothermic?
a)
b)
c)
d)

58) For the combustion of methane at 250C, the difference between H and E will be
a) – 4 x 4.184 x 298 J
b) +4 x 4.184 x 298 J
c) -2 x 4.184 x 298 J
d) zero

59) In which of the following does the entropy decrease?
a) Crystallisation of sucrose from solution
b) Conversion of diamond to graphite
c) Melting of ice
d) Vaporization of camphor

60) An endothermic reaction is allowed to take place rapidly in the air. The temperature of the surrounding air
a) remains constant
b) increases
c) decreases
d) cannot answer as sufficient information is not available

61) A mixture of 2 moles of carbon monoxide and one mole of oxygen in a closed vessel is ignited to get carbon dioxide. If DH is the enthalpy change and DE is the change in internal energy then
a)
b)
c)
d) Not definite

62) If DHf(X), DHf(Y), DHf(R) and DHf(S) denote the enthalpies of formation of X,Y,R and S respectively the enthalpy of the reaction X + Y ® R + S is given by
a)
b)
c)
d)

63) For the transition C (diamond) C (graphite); = -1.5 kJ. It follows that
a) diamond is exothermic
b) graphite is endothermic
c) graphite is more stable than diamond
d) diamond is more stable than graphite.

64) If a chemical change is brought about by one or more method, in one or more steps, then the amount of heat absorbed or evolved during the complete change is the same, whichever method was followed. This rule is known as
a) Le Chatelier principle
b)
c) Joule-Thomson effect
d) None of these

65) Which of the following reactions can be used to define the heat of formation of CO2 (g) ?
a)
b)
c)
d)

66) What percent T1 is of T2 for a heat engine whose efficiency is 10 % ?
a) 80 %
b) 90 %
c) 10 %
d) 100 %

67) Which of the following is an endothermic reaction ?
a)
b)
c)
d)

68) The law of Lavoisier and Laplace illustrates
a) the principle of conservation of energy
b) the equivalence of mechanical and thermal energy
c) the principle of conservation of matter
d) the equivalence of mechanical and chemical energy

69) The molar neutralisation heat for KOH and HNO3 as compared to the molar neutralisation heat of NaOH and HCl is
a) less
b) more
c) equal
d) depends on pressure

70) The heat released when NH4OH and HCl neutralise each other is
a) 13.7 kcal
b) > 13.7 kcal
c) < 13.7 kcal
d) none of the above

71) Which one of the following relations is incorrect ?
a)
b)
c)
d)

72) If H+ OH H2O + 13.7 kcal, then the heat of complete neutralization of one gram mole of H2SO4 with a base will be
a) 13.7 kcal
b) 27.4 kcal
c) 6.85 kcal
d) 3.425 kcal

73) A heat engine operating between 2270C and 270C absorbs 2 kcal of heat from the 2270C reservoir per cycle. The amount of work done in one cycle is
a) 0.4 kcal
b) 4 kcal
c) 0.8 kcal
d) 8 kcal

74) If for H2(g) + H2O(g), is the enthalpy of reaction and for H2(g) + H2O(l), is enthalpy of reaction, then
a)
b)
c)
d)

75) The heat of neutralisation is least when
a) NaOH is neutralised by CH3COOH
b)
c) NH4OH is neutralised by CH3COOH
d) NH4OH is neutralised by HNO3

76) Which of the following has the maximum caloric value ?
a) Charcoal
b) Kerosene
c) Wood
d) Cow dung

77) For an adiabatic process, which of the following is correct ?
a)
b) q = +W
c)
d) q = 0

78) According to equation which factor affects the heat of reaction ?
a) Pressure
b) Temperature
c) Volume
d) Molecularity

79) For a reaction to be spontaneous at all temperatures
a)
b)
c)
d)

80) All reactions with chemical dissociation are
a) reversible
b) reversible and endothermic
c) exothermic
d) reversible or irreversible and endothermic or exothermic

81) For a reaction which of the following statements is correct?
a)
b)
c)
d)

82) @ 1 mole of ice is converted to liquid at 273 K; H2O (s) and H2O (l) have entropies 38.20 and 60.03 J mol-1 deg-1. The enthalpy change in the conversion will be
a) 59.59 J / mol
b) 595.95 J / mol
c) 5959.5 J / mol
d) 595959.0 J / mol

83) What is the free energy change, G, when 1.0 mole of water at 1000C and 1 atm pressure is converted into steam at 1000C and 1 atm pressure ?
a) 540 cal
b) -9800 cal
c) 9800 cal
d) 0 cal

84) Equal volumes of molar hydrochloric acid and sulphuric acid are neutralized by dil. NaOH solution, and x kcal and y kcal of heat are liberated respectively. Which of the following is true ?
a) x = y
b)
c) x = 2y
d) None of these

85) Which of the following values of heat of formation indicates that the product is least stable ?
a) -94 kcal
b) -231.6 kcal
c) + 21.4 kcal
d) +64.8 kcal

86) Thermodynamic equilibrium involves
a) Chemical equilibrium only
b) Thermal equilibrium and chemical equilibrium only
c) Mechanical equilibrium and thermal equilibrium only
d) All the above

87) A system changes its state from A to B. The resulting change of entropy will be a definite quantity
a) When the change is a reversible one only
b) When the change is an irreversible one only
c) When the change is an isothermal one only
d) Always, irrespective of the manner in which the change is brought about

88) A particular reaction has a negative value for the free energy change. Then at an ordinary temperature
a) it has a large negative value for the entropy change
b) it has a large positive value for the enthalpy change
c) it has a small positive value for the enthalpy change
d) it has a positive value for the entropy change and a negative value for the enthalpy change

89) The heat absorbed in a reaction at constant temperature and volume is equal to
a)
b)
c)
d)

90) At equilibrium, is
a) positive
b) negative
c) zero
d) none of the above(a – c)

91) In which of the following neutralization reactions will the heat of neutralization be the highest ?
a)
b)
c)
d)

92) For the spontaneity of a reaction which statement is true ?
a)
b)
c)
d)

93) The enthalpy of a compound is equal to its
a) heat of combustion
b) heat of formation
c) heat of reaction
d) heat of solution

94) Which of the following is true for the reaction H2O (g) at 1000 C and 1 atmosphere ?
a)
b)
c)
d)

95) For the reaction 2 NH3, = ?
a)
b)
c)
d)

96) Enthalpy change for the reaction C + O2 CO2 is
a) positive
b) negative
c) zero
d) none

97) During the isothermal expansion of an ideal gas its
a) internal energy increases
b) enthalpy decreases
c) enthalpy remains unaffected
d) enthalpy reduces to zero

98) The amount of heat measured for a reaction in a bomb calorimeter is
a)
b)
c)
d)

99) For a system in equilibrium, = 0, under conditions of constant
a) temperature and pressure
b) temperature and volume
c) energy and volume
d) pressure and volume

100) For an endothermic reaction where represents the enthalpy of the reaction in kJ/mol, the minimum value for the energy of activation will be
a)
b) zero
c)
d)


Answer :

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