CHEMICAL THERMODYNAMICS – 3

1) If 900 J/g of heat is exchanged at the boiling point of water, then what is the increase in entropy ?
a) 43.4 J / mole
b) 87.2 mole
c) 900 J / mole
d) zero

2) For an ideal gas, the relation between the enthalpy change and the internal energy change at constant temperature is given by
a)
b)
c)
d)

3) An exothermic reaction is one in which the reacting substances
a) Have more energy than the products
b) Have less energy than the products
c) Have the same energy as the products
d) Are at a higher temperature than the products

4) A well-stoppered perfectly insulated flask contains some ice cubes. This is an example of
a) a closed system
b) an open system
c) an isolated system
d) a non-thermodynamic system

5) 1 g ice absorbs 335 J of heat to melt at 00C. The entropy change will be
a)
b)
c)
d)

6) Which one of the following bonds has the highest average bond energy (kcal/mole) ?
a) S = O
b) C = C
c)
d)

7) The relation between and at constant pressure is
a)
b)
c)
d)

8) Identify the state function among the following
a) q
b) q – w
c) q / w
d) q + w

9) When ice melts into water, entropy
a) becomes zero
b) decreases
c) increases
d) remains same.

10) At a given temperature, the energy of activation of two reactions is the same if
a) the specific rate constant for the two reactions is the same
b) the temperature coefficient for the specific rate constant for the two reactions is the same
c)
d)

11) Which among the following is not a state function of a thermodynamic system?
a) Internal energy(E)
b) Free energy(G)
c) Enthalpy(H)
d) Work(W)

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

13) An isolated system is that system in which
a) there is no exchange of energy with the surroundings
b) there is exchange of mass and energy with the surroundings
c) there is no exchange of mass and energy with the surroundings
d) there is exchange of mass with the surroundings

14) Since the enthalpy of elements in their natural state is taken to be zero, the heat of formation of compounds
a) always negative
b) is always positive
c) May be negative or positive
d) is zero

15) In a reaction the
a) heat of reaction
b) heat of combustion
c) heat of formation
d) heat of solution

16) The enthalpy change (-) for the neutralization of 1 M HCl by caustic potash in dilute solution at 298 K is
a) 68 kJ
b) 65 kJ
c) 57.3 kJ
d) 50 kJ

17) The evaporation of water is
a) An exothermic change
b) An endothermic change
c) A process where no heat changes occur
d) A process accompanied by chemical reaction

18) Identify the set of intensive quantities from the following:
a) Enthalpy and temperature
b) Volume and temperature
c) Enthalpy and volume
d) Temperature and refractive index.

19) At constant T and P which one of the following statements is correct for the reaction ?

a)
b)
c)
d)

20) Which of the following statement is true ? The entropy of the universe
a) increases and tends towards a maximum value
b) decreases and tends to zero
c) remains constant
d) decreases and increases with a periodic rate.

21) The total entropy change for a system and its surroundings increases, if the process is
a) reversible
b) irreversible
c) exothermic
d) endothermic

22) In a reversible isothermal process, the change in internal energy is
a) zero
b) positive
c) negative
d) none of these

23) The heat of combustion of carbon is -94 kcal at 1 atm pressure, the intrinsic energy of CO2 is
a) +94 kcal
b) -94 kcal
c) +47 kcal
d) -47 kcal

24) will be highest for the reaction
a)
b)
c)
d)

25) The heat of neutralization of aqueous hydrochloric acid by NaOH is x kcal/mole of HCl. Calculate the heat of neutralization per mole of aqueous acetic acid.
a) 0.5 x kcal
b) x kcal
c) 2 x kcal
d) cannot be calculated from the given data

26) The free energy change = 0, when
a) the system is in equilibrium
b) a catalyst is added
c) the reactants are initially mixed thoroughly
d) the reactants are completely consumed.

27) The heat of neutralization of a strong acid against a strong base is constant and is equal to (1) 13.7 kcal; (2)57kJ;(3) 5.7 X 10 4J
a) Only (1) is correct.
b) (2) and (3) are correct, not (1)
c) only (2) is correct
d) all three are correct

28) The heat of combustion of acetylene is
a) +228 kJ
b) – 228 kJ
c) +100 kJ
d) – 100 kJ

29) Which equation is correct ?
a)
b)
c)
d)

30) When water is added to quick lime, the reaction is
a) explosive
b) endothermic
c) exothermic
d) photochemical

31) A gas absorbs 250 J of heat and expands from 1 litre to 10 litre at constant temperature against an external pressure of 0.5 atm. The values of q, w and E will be respectively.
a) 250 J, 455 J, 710 J
b) 250 J, -455 J, -205 J
c) -250 J, -455 J, -205 J
d) -250 J, 455 J, 205 J

32) The calorific value of fat is
a) less than that of carbohydrates and protein
b) less than that of protein but more than carbohydrates
c) less than that of carbohydrates but more than that of protein
d) more than that of carbohydrate and protein

33) Which of the following is a closed system ?
a) a jet engine
b) Tea placed in a steel kettle
c) a pressure cooker
d) a rocket engine during propulsion

34) For a reaction to occur spontaneously
a)
b)
c)
d)

35) For the reaction C + O2 CO2
a)
b)
c)
d) None of these.

36) Heat capacity is
a)
b)
c)
d) None of these

37) The value of free energy change at equilibrium is
a) positive
b) negative
c) zero
d) not definite

38) The enthalpy of a reaction is expressed as
a)
b)
c)
d)

39) According to the third law of thermodynamics, which one of the following quantities for a perfectly crystalline solid is zero at absolute zero ?
a) Entropy
b) Free energy
c) Internal energy
d) Enthalpy

40) The standard free energy change, is related to the equilibrium constant, KP as
a)
b)
c)
d)

41) The enthalpy change of a reaction does not depend on
a) the state of the reactants and products
b) the nature of the reactants and products
c) different intermediate reactions
d) the initial and final enthalpy change of a reaction.

42) Given that C + O2 CO2 = – x kJ
2 CO + O2 2 CO2 = – y kJ, the enthalpy of formation of carbon monoxide will be

a)
b)
c)
d)

43) The enthalpy of neutralisation of acetic acid and sodium hydroxide is -55.4 kJ. What is the enthalpy of ionisation of acetic acid ?
a) -1.9 kJ
b) +1.9 kJ
c) +5.54 kJ
d) -5.54 kJ

44) The enthalpy change of a system depends upon its
a) Initial state
b) Final state
c) initial and final state
d) None of these

45) The relationship between enthalpy change and internal energy change is
a)
b)
c)
d)

46) In an adiabatic process, which of the following is true ?
a) q = +W
b) q = 0
c)
d)

47) Mark the correct statement:
a)
b) Entropy is a measure of order in a system
c)
d) The total energy of an isolated system is constant

48) For the reaction , which one of the following statements is correct at constant T and P?
a)
b)
c)
d)

49) The relation between enthalpy (H), pressure (P), volume (V) and internal energy (E) is given by
a) E = H + PV
b) H = E + PV
c) H = E – PV
d) H = E + P + V

50) The enthalpy and entropy change for a chemical reaction is -2.5 x 103 cal and 7.4 cal deg-1 respectively. The reaction at 298 K will be
a) spontaneous
b) reversible
c) irreversible
d) non – spontaneous

51) The heat exchanged in a chemical reaction at constant temperature and constant pressure is called
a) internal energy
b) enthalpy
c) entropy
d) free energy

52) @ Given the reaction at 1240 K and 1 atm. CaCO3 (s) CaO (s) + CO2 (g), H = 176 kJ / mol, the E equals
a) 160.0 kJ
b) 165.6 kJ
c) 186.4 kJ
d) 180.0 kJ

53) The neutralization of a strong acid by a strong base liberates an amount of energy per mole of H+ which
a) depends upon which acid and base are involved
b) depends upon the temperature at which the reaction takes place
c) depends upon which catalyst is used
d) is the same regardless of which acid is used

54) Equal volumes of methanoic acid and sodium hydroxide are mixed. If x is the heat of formation of water, then the heat evolved on neutralisation is
a) more than x
b) equal to x
c) less than x
d) twice x

55) One mole of an ideal gas is allowed to expand freely and adiabatically into vacuum until its volume has doubled. The expression which is not true concerning the above statement is
a)
b)
c)
d)

56) For which of these processes is negative ?
a)
b)
c)
d)

57) The energy change of the reaction The bond energy of the C — H bond is
a) X/6 kJ
b) X/3 kJ
c) X kJ
d) Indeterminate, from the data given

58)
. Find out the heat of formation of SO2

a) (2x – y)
b) (2x + y)
c) (x + y)
d) 2x / y

59) For the process Dry ice CO2 (g)
a)
b)
c)
d)

60) Given

. The heat of combustion of

a) -807 kJ mol
b) -1104 kJ / mol
c) + 1104 kJ / mol
d) + 807 kJ / mol

61) The enthalpy of formation for C2H4 (g), CO2 (g) and H2O (l) at 250C and 1 atm pressure are 52, -394 and -286 kJ mol-1 respectively. The enthalpy of combustion of C2H4 (g) will be
a) +1412 kJ / mol
b) – 1412 kJ / mol
c) + 141.2 kJ /mol
d) – 141.2 kJ / mol

62) The standard molar heat of formation of ethane, CO2 and water (l) are respectively -21.1, -94.1 and -68.3 kcal. The standard molar heat of combustion of ethane will be
a) -372 kcal
b) 162 kcal
c) -240 kcal
d) 183.5 kcal

63) The heat of formation of CO and CO2 are -26.4 kcal and -94.6 kcal respectively. The heat of combustion of carbon monoxide will be
a) + 26.4 kcal
b) – 68.2 kcal
c) -120.6 kcal
d) + 52.8 kcal

64) Given the following entropy values (in JK-1 mol-1) at 298 K and 1 atm : H2 (g) : 130.6, Cl2 (g) : 223.0 and HCl (g) : 186.7. The entropy change (in JK mol-1) for the reaction H2 (g) + Cl2(g) 2HCl (g) is
a) +540.3
b) +727.0
c) -166.9
d) 19.8

65) The heat of combustion of benzene at 270C found by the bomb calorimeter. i.e., for the reaction is 780 kcal mol. The heat evolved on burning 39 g of benzene in an open vessel will be
a) 390 kcal
b) 780.9 kcal
c) 390.45 kcal
d) 780 kcal

66) When 0.2 g of butanol-1 was burnt in a suitable apparatus, the heat evolved was sufficient to raise the temperature of 200 g of water by 50C. The heat of combustion of butanol – 1 in kcal/mole will be (mol mass of butanol-1 = 74)
a) 14.8
b) 74
c) 37
d) 370

67) The heat of combustion of sucrose is 1350 kcal. How much of heat will be liberated when 17.1 g of sucrose is burnt ?
a) 67.5 kcal
b) 13.5 kcal
c) 40.5 kcal
d) 25.5 kcal

68) The heat evolved in the combustion of glucose is given by the equation . The weight of CO2 gas produced when 170 kcal of heat is evolved in the combustion of glucose is
a) 264 g
b) 66 g
c) 11 g
d) 44 g

69) The difference between the heats of reaction at constant pressure and constant volume for the reaction 2 C6H6 (l) + 15 O2 (g) 12 CO2 (g) + 6 H2O (l) at 250 C in kJ is
a) -7.43
b) +3.72
c) -3.72
d) +7.43

70) One mole of an ideal gas is allowed to expand reversibly and adiabatically from a temperature of 270C. If the work done during the process is 3 kJ, the final temperature will be equal to (Cv = 20 J/K)
a) 150 K
b) 100 K
c) 26.85 K
d) 295 K

71) If S + O2 SO2, = -298.2 kJ
SO2 + O2 SO3, = -98.7 kJ, SO3 + H2O H2SO4, = -130.2 kJ
H2 + O2 H2O, = -287.3 kJ. Then the enthalpy of formation of H2SO4 at 298 K will be

a) -814.4 kJ
b) +320.5 kJ
c) -650.3 kJ
d) -933.7 kJ

72) An ideal gas expands from 10-3 m3 to 10-2 m3 at 300 K against a constant pressure of 105 N / m2. The work done is
a)
b)
c) -0.9 kJ
d) -900 kJ

73) The enthalpy at 298 K of the reaction H2O2 (l) H2O (l) + O2 (g) is -23.5 kcal mol-1 and the enthalpy of formation of H2O2 (l) is -44.8 kcal mol-1. The enthalpy of formation of H2O(e)is
a) -68.3 kcal / mol
b) 68.3 kcal / mol
c) -91.8 kcal / mol
d) 91.8 kcal / mol

74) The heat of combustion of CH4 (g), C (graphite), H2 (g) are -20 , -40 , -10 respectively expressed in arbitrary units. The heat of formation of methane is
a) -40
b) +40
c) -80
d) +80

75) The work done in ergs for the reversible expansion of one mole of an ideal gas from a volume of 10 litres to 20 litres at 25o C is
a)
b)
c)
d)

76) The enthalpies of combustion of carbon and carbon monoxide are -390 kJ mol and -278 kJ mol respectively. The enthalpy of formation of carbon monoxide is
a) 668 kJ / mol
b) 112 kJ / mol
c) -112 kJ / mol
d) -668 kJ / mol

77) H2 + Cl2 2 HCl, = -194 kJ. In this reaction, the heat of formation of HCl in kJ is
a) +194 kJ
b) + 97 kJ
c) -97 kJ
d) -194 kJ

78) Heat of neutralisation for the reaction NaOH + HCl NaCl + H2O is 57.1 kJ mol. What will be the heat released when 0.25 mole of NaOH reacts with 0.25 mole of HCl ?
a) 22.5 kJ / mol
b) 57.1 kJ / mol
c) 14.3 kJ / mol
d) 28.6 kJ / mol

79) The heat of neutralisation of a strong acid and a strong alkali is 57.0 kJ mol. The heat released when 0.5 mole of HNO3 solution is mixed with 0.2 mole of KOH is
a) 57.0 kJ
b) 11.4 kJ
c) 28.5 kJ
d) 34.9 kJ

80) When 20 ml of a strong acid is added to 20 ml of an alkali, the temperature rises by 50C. If 200 ml of each liquid are mixed, the temperature rise would be
a)
b)
c)
d)

81) Under the same conditions how many ml of 1 M KOH and 0.5 H2SO4 solutions, respectively, when mixed to form a total volume of 100 ml. produce the highest rise in temperature ?
a) 67,33
b) 33,67
c) 40,60
d) 50,50

82) If the enthalpy of vaporisation of a liquid at 373k is 186.5 J / mol, the entropy of its vaporisation will be
a)
b)
c)
d)

83) If the heat of dissolution of anhydrous CuSO4 and CuSO4. 5H2O are -15.89 kcal and + 2.80 kcal respectively, then the heat of hydration of CuSO4 to form CuSO4. 5H2O is
a) -13.09 kcal
b) -18.69 kcal
c) +13.09 kcal
d) +18.69 kcal

84) The heats of combustion of graphite and diamond are 393.5 and 395.4 kJ / mole respectively. The heat of transformation of graphite to diamond will be
a) -1.9 kJ / mole
b) +1.9 kJ / mole
c) 788.7 kJ / mole
d) -788.7 kJ / mole

85) The heats of combustion of rhombic and monoclinic sulphur are respectively 70960 and 71030 calories. What will be the heat of conversion of rhombic sulphur to monoclinic ?
a) 70960 calories
b) 71030 calories
c) -70 calories
d) +70 calories

86) The heat of combustion of yellow P and red P are -9.91 kJ mol and -8.78 kJ mol respectively. The heat of transition of yellow P red P is
a) -18.69 kJ
b) +1.13 kJ
c) +18.69 kJ
d) -1.13 kJ

87) The for CO2 (g), CO (g) and H2O (g) are -393.5, -110.5 and -241.8 kJ mol respectively. The standard enthalpy change (in kJ) for the reaction
CO2 (g) + H2 (g) CO (g) + H2O (g) is

a) 524.1
b) 41.2
c) -262.5
d) -41.2

88) H2 (g) + Cl2 (g) 2HCl (g), = -44 kcal
2 Na (s) + 2 HCl (g) 2 NaCl (s) + H2 (g), = -152 kcal. For the reaction, Na (s) + Cl2 (g) NaCl (s), = ?

a) -180 kcal
b) -196 kcal
c) -98 kca
d) 54 kcal

89) The enthalpies of formation of N2O and NO are 82 and 90 kJ / mole respectively. The enthalpy of the reaction 2 N2O (g) + O2 (g) 4 NO (g) is equal to
a) 8 kJ
b) 88 kJ
c) -16 kJ
d) 196 kJ

90) Based on the following thermochemical equations
H2O (g) + C (s) CO (g) + H2 (g) ; = 131 kJ
CO (g) + O2 (g) CO2 (g); = -282 kJ
H2 (g) + O2 (g) H2O (g); = -242 kJ
C (s) + O2 (g) CO2 (g); = X kJ, the value of X will be

a) -393 kJ
b) -655 kJ
c) +399 kJ
d) +655 kJ

91) The enthalpy of formation of ammonia is -46.0 kJ / mol. The enthalpy for the reaction 2N2 (g) + 6 H2 (g) 4 NH3 (g) is equal to
a) -46.0 kJ
b) 46.0 kJ
c) 184.0 kJ
d) -184.0 kJ

92) The enthalpy of combustion at 250 C of H2, cyclohexene (C6H10) and cyclohexane (C6H12) are -241, -3800 and -3920 kJ / mol respectively. The heat of hydrogenation of cyclohexene is
a) -121 kJ / mole
b) + 121 kJ / mole
c) – 242 kJ / mole
d) + 242 kJ / mole

93) If for H2O2 and H2O are -188 kJ / mole and -286 kJ / mole, what will be the enthalpy change of the reaction 2H2O2 (l) 2H2O (l) + O2 (g) ?
a) -196 kJ / mole
b) 146 kJ / mole
c) -494 kJ / mole
d) -98 kJ / mole

94) The standard heats of formation in kcal / mole of NO2 (g) and N2O4 (g) are 8.0 and 2.0 respectively. The heat of dimerisation of NO2 i.e., for NO2 (g) N2O4 (g) in kcal is
a) 10.0
b) -6.0
c) -12.0
d) -14.0

95) The heats of formation for SiO2 and MgO are -48.4 and -34.7 kJ respectively. The heat of the reaction 2 Mg + SiO2 2 MgO + Si is
a) 21.0 kJ
b) -21.0 kJ
c) 13.7 kJ
d) -13.7 kJ

96) Considering the following reactions, C + O2 CO, = -26. 4 k
H2 + O2 H2O (l), = -57.8 kcal, for the reaction H2O + C H2 + CO is

a) 62.8 kcal
b) 31.4 kcal
c) -31.4 kcal
d) -84.2 kcal

97) Given C(graphite) + O2 (g) CO (g); = -110.5 kJ
CO (g) + O2 (g) CO2 (g); = -283.2 kJ. The heat of reaction for C (graphite) + O2 (g) CO2 (g) will be

a) -393.7 kJ
b) + 393.7 kJ
c) -172.2 kJ
d) +172.2 kJ

98) of CO2 (g), CO (g), N2O (g) and NO2 (g) in kJ / mol are respectively -393, -110, 81 and 34. Calculate the in kJ of the following reaction :2 NO2 (g) + 3 CO (g) N2O (g) + 3 CO2 (g)
a) 836
b) 1460
c) -836
d) -1460

99) When Zn dust is added to a sufficiently large volume of an aqueous solution of copper sulphate, 3.175 g of copper metal and 20 J of heat is evolved. The for the reaction Zn (s) + CuSO4 (aq) ZnSO4 (aq) + Cu (s) is (at wt of Zn = 65.3, at wt of Cu = 63.5)
a) 20 J
b) 200 J
c) 400 J
d) 65.3 J

100) The enthalpy of vapourization of liquid water using the data H2 (g) O2+ (g) H2O (l); = -285.77 kJ / mole H2 (g) + O2 (g) H2O (g); = -241.84 kJ / mole is
a) 43.9 J
b) 200 J
c) 400 J
d) 65.3 J


Answer :

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