Chemical Thermodynamics MHT-CET PYQ's

 

 MHT-CET 2004 

1. If the heat of formation of CO2 is -393 kJ. The amount of heat evolved in the formation of 0.176 kg of CO2 is

• (A) -1357.9 kJ
• (B) -1275.9 kJ 
• (C) -1572.0 kJ
• (D) -1165.5 kJ

2. Enthalpy (H) is equal to

• (A) internal energy (U)        
• (B) product of pressure (P) and volume (V) of gas        
• (C) internal energy (U) + PV        
• (D) work (W) done by a system

 

3. For the reaction, PCI5 (g) ---> PCI3(g)+ C12(g) 

• (A) △H = △U     
• (B) △H > △U         
• (C) △H < △U        
• (D) None of these

 
MHT-CET 2005 

4. Bond energy of hydrogen gas is - 433 kJ. How much is the bond dissociation energy of 0.5 mole of hydrogen gas? 

• (A) - 433 kJ         
• (B) + 433 kJ         
• (C) - 216 kJ         
• (D) + 216 kJ

5. Heat of formation of SO2 is -298 kJ. What is the heat of combustion of 4 g of S? 

• (A) +37 kJ         
• (B) -37.15 kJ         
• (C) + 298 kJ         
• (D) 18.6 kJ

6. 2 moles of helium gas expanded isothermally and irreversibly at 27°C from volume 1 dm³ to 1 m³ at constant pressure of 100 kPa. Calculate the work done.

• (A) 99900 kJ         
• (B) 99900 J         
• (C) 34464.65 kJ         
• (D) 34464.65 J 

MHT-CET 2006

7. The standard molar heat of formation of ethane, CO2 and water (l) are -21.1, -94.1 and -68.3 kcal respectively. The standard molar heat of combustion of ethane will be

• (A) -372 kcal         
• (B) 162 kcal         
• (C) -240 kcal         
• (D) 183.5 kcal

8 In a closed container, a liquid is stirred with a paddle to increase the temperature. Which of the following is true? 

• (A) △U = W ≠ 0, Q = 0         
• (B) △U = W = Q ≠ 0         
• (C) △U = 0, W = Q ≠ 0         
• (D) W = 0, △U = Q ≠ 0 

MHT-CET 2007

9. Which of the following is a path function?

• (A) Internal energy     
• (B) Enthalpy    
• (C) Work     
• (D) Entropy 

10. Hess's law is based on

1. (A) Law of conservation of mass
2. (B) Law of conservation of energy  
3. (C) First law of thermodynamics  
4. (D)None of these 

11. For an ideal gas, the heat of reaction at constant pressure and constant volume are related as 

• (A) H + U = PV 
• (B) U = H + P△V
• (C) Qp = Qv + △nRT
• (D) None of these

12. For the reaction, 2H2(g) + O2(g) → 2H2O(g), (△H = -573.2 kJ) The heat of decomposition of water per mole is 

• (A) 286.6 kJ 
• (B) 573.2 kJ
• (C) -28.66 kJ
• (D) zero

13. The bond energy is the energy required to

• (A) dissociate one mole of the substance 
• (B) dissociate bond in 1 kg of the substance
• (C) break one mole of similar bonds 
• (D) break bonds in one mole of substance

MHT-CET 2008 

14. 1f △U is the heat of reaction for C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l) at constant volume, the △H (heat of reaction at constant pressure), at constant temperature is

• (A) △H = △U + RT 
• (B) △H = △U - RT
• (C) △H = △U - 2 RT
• (D) △H = △U + 2RT 

MHT-CET 2009 

15. Heat of combustion of methane is - 800 kJ. What is the heat of combustion for 4 x 10^-4 kg of methane? 

• (A) - 800 kJ 
• (B) -3.2 x 10⁴ kJ 
• (C) - 20 kJ 
• (D) - 1600 kJ

16. 16 g of oxygen gas expands isothermally and reversibly at 300 K from 10 dm³ to 100 dm³. The work done is (in J) 

• (A) zero 
• (B) - 2875 J 
• (C) +2875 J
•  (D) infinite 

17. At the same conditions of pressure, volume and temperature, work done is maximum for which gas if all gases have equal masses? 

• (A) NH3 
• (B) N2
• (C) Cl2
•  (D) H2S

18. In ......... process, work is done at the expense of internal energy

•  (A) isothermal
•  (B) isochoric 
•  (C) adiabatic 
• (D) isobaric

MHT-CET 2010

19. The heat of formation of water is 260 kJ. How much H2O is decomposed by 130 kJ of heat? 

• (A) 0.25 mol
• (B) 1 mol 
• (C) 0.5 mol
• (D) 2 mol

MHT-CET 2011 

20. The heat of combustion of carbon is -393.5 kJ/mol. The heat released upon the formation of 35.2 g of CO2 from carbon and oxygen gas is 

• (A) +315 kJ 
• (D) -31.5 kJ
• (B) -315 kJ
• (C) -31.5 kJ

21. According to Hess's law, the heat of reaction depends upon

• (A) initial condition of reactanrs
• (B) initial and final condition of reactants
• (C) intermediate path of the reaction 
• (D) end conditions of reactant

MHT-CET 2014

22. Find the correct equation. 

• (A) U₂ - U¹ - H₂+ H¹ = n₂RT - n¹RT
• (B) U₂ - U¹ - H₂ - H¹ = n₂RT + n¹RT
• (C) H₂ - H¹ - U₂ + U¹ = n₂RT - n¹RT
• (D) H₂ - H¹ - U₂ + U¹ = n₂RT + n¹RT  

23. Assuming enthalpy of combustion of hydrogen at 273 K is -286 kJ and enthalpy of fusion of ice at the same temperature to be +6.0 kJ. calculate enthalpy change during formation of 100 g of Ice. 

• (A) + 1622 kJ
• (B) -1622 kJ
• (C) + 292 kJ
• (D) - 292 kJ

24. The work done when two moles of an ideal gas is compressed from a volume of 5m³ to 1dm³ at 300 K, under a pressure of 100 kPa is

• (A) 499.9 kJ 
• (B) - 499.9 kJ 
• (C) - 99.5 kJ 
• (D) 42495 kJ

MHT-CET 2015
25. For which among the following reactions, change in entropy is less than zero? 

• (A) Sublimation of Iodine
• (B) Dissociation of Hydrogen 
• (C) Formation of water 
• (D)Thermal decomposition of Calcium Carbonate

26. Given R = 8.314 JK^-1 mol^-1, the work done during combustion of 0.090 kg of ethane (Molar mass = 30) at 300 K is

• (A) - 18.7 kJ
• (B) 18.7 kJ
• (C) 6.234 kJ
• (D) - 6.234 kJ

27. Which among the following is a feature of adiabatic expansion?

• (A) △V < 0
• (B) △U < 0
• (C) △U > 0
• (D) △T = 0

28. What is the amount of work done when two moles of ideal gas is compressed from a volume of 1 m³ to 10 dm³ at 300 K against a pressure of 100 kPa?

• (A) 99 kJ
• (B) - 99 kJ
• (C) 114.9 kJ
• (D) - 114.9 kJ

MHT-CET 2016 

29. Mathematical equation of first law of thermodynamics for isochoric process is

• (A) △U = Qv
• (B) -△U = Qv
• (C) Q = -W
• (D) △U = W 

30. The criterion for a spontaneous process is 

• (A) △G > 0
• (B) △G < 0
• (C) △G = 0 
• (D) △S(total) < 0

31. Identify an extensive property amongst the following. 

• (A) Viscosity 
• (B) Heat capacity 
• (C) Density
• (D) Surface tension
  

32. What is the amount of work done when 0.5 mole of methane, CH4(g), is subjected to combustion at 300K? (Given, R = 8.314 J K^-1 mol^-1)

• (A) - 2494 J
• (B) - 4988 J 
• (C) + 4988 J
• (D) + 2494 J

MHT-CET 2017

33. The work done during combustion of 9 x 10^-2 kg of ethane, C2H6 (g) at 300 K is (Given: R = 8.314 J K^-1 mol^-1, Atomic mass: C = 12, H = 1) 

• (A) 6.236 kJ 
• (B) -6.236 kJ
• (C) 18.71 kJ 
• (D) -18.71 kJ

34. Calculate the work done during compression of 2 mol of an ideal gas from a volume of 1m³ to 10 dm³ at 300 K against a pressure of 100 kPa. 

• (A) -99 kJ
• (B)  +99 kJ
• (C) +22.98 kJ
• (D) -22.98 k

35. The first law of thennodynattrics tbr isothermal process is

• (A) Q = -W
• (B) △U = W
• (C) △U = Qv
• (D) △U = -Qv

36. Identify the INVALID equation.

• (A) △H = ∑H(products) - ∑H(reactants)
• (B) △H = △U + P△V
• (C) △H(reaction) = ∑H(product bonds) - ∑H(reactant bonds)
• (D) △H = △U + △nRT

MHT-CET 2018

 37. Which among the rollowing equations represents the first law of thermodynamics under isobaric condition?

• (A) △U = Qp - P.△V
  
• (B) Q = △U
• (C) △U = W
• (D) W = -Q 

38. Two moles of an ideal gas are allowed to expand from a volume of 10 dm³ to 2 m³ at 300 k against a pressure of 101.325 kPa. Calculate the work done.

• (A) -201.6 kJ
• (B) 13.22 kJ
• (C) -810.6 kJ
  
• (D) -18.96 kJ

39. Calculate the work done during combustion of 0.138 kg of ethanol. C2H5OH(l) at 300 k. Given R = 8.314 J K^-1 mol^-1, molar mass of ethanol = 46 g mol^-1.

• (A) -7482 J
• (B) 7482 J 
• (C) -2494 J
• (D) 2494 J

MHT-CET 2019

40. For a process. entropy change of a system is expressed as

• (A) Qrev/T
• (B) Qrev x T 
• (C) H -TS
• (D) T/Qrev

41. Calculate the difference between heat of combustion of carbon monoxide gas at constant pressure and at constant volume at 27°C ? (R = 2 cal K^-1 mol^-1)

• (A) 27 cal
• (B) - 300 cal
• (C) 54 cal 
• (D) - 600

42.Three moles of an ideal gas are expanded isothermally from a volume of 300cm³ to 2.5 L at 300 K against a pressure of 1.9 atm. The work done in joules is 

• (A) -4.18 J 
• (B) +423.56 J
• (C) +4.8 J
• (D) -423.56 J

43. Identify the equation in which change in enthalpy is equal to change in internal energy.

• (A) N2(g) + 3H2(g) → 2NH3(g)
• (B) C(s) + O2(g) → CO2(g)
• (C) 2H2O2(l) → 2H2O(l) + O2(g)
• (D) PCl5(g) → PCl3(g) + Cl2(g)

44. If C(s) + O2(g) → CO2(g) △H = -X, CO(g) + 1/2O2(g) → CO2(g) △H = -Y, calculate △H for CO formation :

• (A) Y - X 
• (B) X + Y 
• (C) -Y - X
• (D) X - Y

45. "The mass and energy both are conserved in an isolated system", is the statement of

• (A) Modified rust law of thermodynamics 
• (B) Second law of thermodynamics
• (C) First law of thermodynamics 
• (D) Third law of the thermodynamics

46. Based on first law of thermodynamics which of the following is correct?

• (A) For an isochoric process, △U = -Qv
• (B) For an adiabatic process, △U = -W
• (C) For an isobaric process, Qp = △U + W
• (D) For an isothermal process, Q = +W

47. A gas performs 0.320 kJ work on surrounding and absorbs 120 J of heat from the surrounding Hence change in internal energy is 

• (A) 440 J
• (B) 120.32 J
• (C) 200 J 
• (D) -200 J

48. Consider the following reaction H2(g) + C12(g) → 2HC1(g) + 44 kcal. Calculate heat of formation for 36.5 g of HCl.

• (A) - 44 kcal 
• (B) - 88 kcal 
• (C) - 22 kcal
• (D) 11 kcal

49. One mole methanol is formed from its elements under standard condition with liberation of 238.9 kJ of heat energy. What is the value of △S(surr.) ? 

• (A) 711.7 J 
• (B) 801.7 J 
• (C) 472.8 J 
• (D) 238.91 

50. For a reaction to be non-spontaneous at all temperatures, values of △H and △S respectively are 

• (A) negative, negative 
• (B) positive, positive 
• (C) negative, positive 
• (D)positive, negative 

51. If C(graphite) + O2(g) → CO2(g), △H° = -393.5 kJ. C(diamond) + O2(g) → CO2(g), △H° = -395.4 kJ. What is enthalpy of transformation of C(graphite) → C(diamond) ?

• (A) -1.9 kJ
• (B) 788.9 kJ
• (C) 1.9 kJ
• (D) 589.5 kJ
  

52. When 2.3 g of gaseous sodium is ionized, 49.4 kJ of heat is required. What is enthalpy of ionization of sodium? 

• (A) 49.0 kJ mol^-1
• (B) 494 kJ mol^-1
• (C) 48.4 kJ mol^-1
• (D) 404 kJ mol^-1

 
53. For a particular reaction, system absorbs 6 kJ of heat and does 1.5 kJ of work on its surrounding. What is enthalpy change of system? 

• (A) + 7.5 kJ
• (B) +6.0 kJ 
• (C) + 4.5kJ
• (D) - 1.5 kJ

54. Calculate standard enthalpy of formation of benzene if, △H°(C6H6)(l) = - 3267 kJ, △H°(CO2)(g) = - 393.5 kJ mol^-1 and △H°(H2O)(l) = -285.8kJ mol^-1.

• (A) -679.3 kJ mol^-1 
• (B) -38.6 kJ mol^-1
• (C) 48.6 kJ mol^-1 
• (D) +32.67 kJ mol^-1

55. Which of the following properties is extensive? 

• (A) Volume 
• (B) Density 
• (C) Melting point 
• (D) Boiling Point 

56. Two moles of an ideal gas is expanded isothermally and reversibly at 300 K from 1L to 10L The enthalpy change in kJ is

• (A) 11.4 kJ 
• (B) -11.4 kJ 
• (C) Zero kJ
• (D) 4.8 kJ

MHT-CET 2020 

57. Enthalpy of fusion and enthalpy of vaporization for water respectively are 6.01 kJ mol^-1 and 45.07 kJ mo1^-1 at 0°C. What is enthalpy of sublimation at 0°C? 

• (A) 48.07 kJ mo1^-1 
• (B) 51.08 kJ mol^-1 
• (C) 27.50 kJ mo1^-1 
• (D) 39.06 kJ mo1-1 

58. For the following reaction :

Fe2O3(s) + 3CO(g) → Fe(s) + 3CO2(s) ; △H° = -29.8 kJ and △S° = 15 JK^-1. What is the value of △S(total) at 298 K? 

• (A) 29.8 J K^-1 
• (B) 298.0 J K^-1 
• (C) 100.0 J K^-1 
• (D) 115.0 J K^-1 
  

59. Which of the following equations is correct for beat of sublimation? 

• (A) △sub.H = △fus.H + △vap.H
• (B) △vap.H = △sub.H + △fus.H 
• (C) △fus.H = △sub.H x △vap.H
• (D) △sub.H = △fus.H - △vap.H 

 60. Which of the following equations has △f.H° and △H° same?

• (A) H2(g) + 1/2O2(g) → H2O(l)
• (B) N2(l) + O3(g) → N2O3(g)
• (C) 2CO(g) + O2(g) → 2CO2(g)
• (D) CH4(g) + 2Cl(g) → CH2Cl2(g) + 2HCl(g)

61. Which 2 moles of an ideal gas are expanded isothermally from a volume of 12.5 L to 15.0 L against constant external pressure of 760 nun Hg. Calculate the amount of work done in joule? 

• (A) -1924.0 J 
• (B) -25.325 J
• (C) -253.25 J
• (D) -190.0 J

62. Which of the following is NOT an intensive property? 

• (A) Surface tension 
• (B) Density 
• (C) Heat capacity 
• (D) Refractive index 

63. For a reaction △H = -30 kJ and △S = -45 J K^-1, at what temperature reaction changes from spontaneous to non-spontaneous? 

• (A) 666.6 K 
• (B) 375.0 K
• (C) 675.0 K 
• (D) 777.0 K 

64. Which of the following compounds is Not present in its standard state at 25°C and 1 atmosphere pressure?

• (A) CaCO3(s) 
• (B) C2H5OH(l) 
• (C) H2O(g)
• (D) CO2(g)

65. Average bond enthalpy of water is 464.5 kJ mol^-1. If the energy required to break first O-H bond is 502 kJ mol^-1, then how much energy per mol is required to break second O-H bond?

• (A) 929 kJ 
• (B) 678 kJ 
• (C) 427 kJ 
• (D) 251 kJ 

66. In an isothermal and reversible process, 1.6 x 10^-2 kg O2 expands from 10 dm³ to 100 dm³ at 300 K. work done in the process is (R = 8.314 JK^-1 mol^-1) 

• (A) -5744 J
  
• (B) -1436 J 
• (C) -2872 J
• (D) -43081 J

67. For the combustion of 1 mole of liquid benzene at 298 K, the heat of reaction at constant pressure is -3268 kJ mol^-1. What is heat of combustion at constant volume? (R = 8.314 x 10^-3 kJ K^-1 mol^-1)

• (A) -6728 kJ mol^-1 
• (B) -672.8 kJ mol^-1
• (C) -3264.2 kJ mol^-1 
• (D) -1632 kJ mol^-1

68. For following reaction, relation between △H and △U is 2SO2(g) + O2(g) → 2SO3(g)

• (A) △H = △U - 2RT 
• (B) △H = △U + RT 
• (C) △H = △U - RT 
• (D) △H = △U + 2RT

69. Heat of combustion of C(s), H2(g) and C2H6(g) are -x1. -x2 and -x3 respectively. Hence heat of formation of C2H6(g) is

• (A) -x3 + 2x1 + 3x3
• (B) -x1 - x2 + x3
• (C) x1 + x2 - x3
• (D) -2x1 - 3x2 + x3      

70. Energy required to dissociate 16g O2(g) into free atoms is x kJ. The value of bond enthalpy of O = O bond is

• (A) 4x kJ
• (B) 2x kJ
• (C) 16x kJ
• (D) x/2 kJ

71. Which is true for heat and temperature?

• (A) Both are intensive properties 
• (B) Intensive and extensive properties respectively
• (C) Both are extensive properrties
• (D) Extensive and intensive properties respectively
  

72. Relation between △H and △U for the reaction, 2SO3(g) → 2SO2(g) + O2(g) is

• (A) △H + △U = RT
• (B) △H + △U = -RT 
• (C) △H - △U = 2RT 
• (D) △H - △U = RT

73. What is the quantity of heat evolved when 6 g carbon combines with sulphur to form CS2 according to the reaction C + S2 → CS2 △H = -92 kJ mol^-1 ? 

• (A) 11 kJ 
• (B) 46 kJ 
• (C) 32 kJ 
• (D) 22kJ 

74. Which of the following conditions indicates the reaction is spontaneous? 

• (A) △S > 0, △H < 0, △G < 0 at all temperature 
• (B) △S < 0, △H > 0, △G > 0 at low temperature 
• (C) △S < 0, △H > 0, △G > 0 at high temperature 
• (D) △S < 0. △H > 0, △G > 0 at all temperature 

75. What is the value of △S(total) for following reaction at 300 K ? 

Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g) (△H° = -25kJ, △S° = 15 JK^-1) 

• (A) 8.32 JK^-1 
• (B) 98.3 JK^-1
• (C) 68.21 JK^-1
• (D) -10.0 JK^-1 

76. Calculate the amount of work done during isothermal expansion of  gas as from a volume of 4 dm³ to 6 dm³ against a constant external pressure of 3 atmosphere? 

• (A) -607.8 J
• (B) -60.8 J 
• (C) -30.4 J
• (D) -6.0 J

77. What is the value of △H° for the formation of ethanol from ethene gas and liquid water from following data? 

C2H5OH(l) + 3O2 → 2CO2(g) + 3H2O(l) △H° = -1368 kJ

C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(l) △H° = 1410 kJ

• (A) +2778.0 kJ 
• (B) -1326.0 kJ 
• (C) +42.0 kJ
• (D) -4188 kJ

78. An ideal gas expands from 1 x 10^-3 m³ to 1 x 10^-2 m³ at 300 K against a constant external pressure of 1 x 10^5N m^-2, work done is 

• (A) -0.7 x 10³ J
• (B) -9 x 10² J
• (C) -9 x 10³ J 
• (D) -1 x 10³ J 

79. When a system absorbs 8 kJ of heat and does 2.2 kJ of work on surrounding, calculate the internal energy change. 

• (A) 5.8 kJ
• (B) 10.8 kJ 
• (C) -10.2 kJ 
• (D) 8.0 kJ 

80. If 38.55 kJ of heat is absorbed when 6.0 g of O2 react with CIF according to reaction 2ClF(s) + O2(g) → Cl2O(g) + OF2(g) What is the standard enthalpy of reaction? 

• (A) 205.6 kJ 
• (B) 102.8 kJ 
• (C) 72.28 kJ 
• (D) 49.80 kJ 

81 A sample of gas absorbs 4000 kJ of heat and surrounding does 2000 J of work on sample. What is the value of △U? 

• (A) 4002 kJ 
• (B) 4000 kJ 
• (C) 2000 kJ 
• (D) 6000 kJ

82. An ideal gas expands isothermally and reversibly from 10 m³ to 20 m³ at 300 K, performing 5.187 kJ of work on surrounding. Calculate number of moles of gas used.

• (A) 3 
• (B) 2 
• (C) 1.5 
• (D) 1

83. Equilibrium constant tor a reaction is 20. What is the value of △G° at 300 K? (R = 8 x 10^-3 kJ) 

• (A) -7.191 kJ mol^-1 
• (B) -2.763 kJ mol^-1
• (C) -5.527 kJ mol^-1 
• (D) 16.63 kJ mol^-1

84. If entropy of a solid is greater than zero, at T = 0, it is called

• (A) absolute entropy
• (B) formal entropy
• (C) residual entropy
• (D) standard entropy

85. Standard enthapy of formation of water -286 kJ mol^-1. When 1800 mg of water is formed from its constituent elements in their standard states the amount of energy liberated is

• (A) 2.86 kJ
• (B) 57.2 kJ
• (C) 5.72 kJ
• (D) 28.6 kJ

86. From the given reaction

N2(g) + 3H2(g) → 2NH3(g) △H = -92.6 kJ, the enthalpy of formation of NH3 is

• (A) -92.6 kJ
• (B) -46.3 kJ
• (C) -185.2 kJ
• (D) -138.9 kJ

87. If 2kJ a heat is released from system and 6 kJ of work is done on the system, what is enthalpy change of system?

• (A) -2 kJ 
• (B) +8 kJ 
• (C) -8 kJ 
• (D) +6 kJ

88. For the reaction, N2(g) + 3H2(g) → 2NH3(g), to △H is equal to

• (A) △U - RT
• (B) △U + 2RT 
• (C) △U + RT 
• (D) △U - 2RT 

89. What is standard N ≡ N bond enthalpy from following reaction?

N2(g) + 3H2(g) → 2NH3(g) △H = -83 kJ

△H(H-H) = 435 kJ, △H(N-H) = 389 kJ

• (A) 2334 kJ
• (B) 435 kJ
• (C) 946 kJ
• (D) 1305 kJ

90. When 6.0 g of graphite reacts with dihydrogen to give methane gas, 37.4 kJ of heat is liberated What is standard enthalpy of formation of CH4(g)?

• (A) -74.8 kJ mol^-1
• (B) -112.2 kJ mol^-1
• (C) -37.4 kJ mol^-1
• (D) 112.2 kJ mol^-1

91. When 1 mole of gas is heated at constant volume and heat supplied is 500 J then which of the
following is correct?

• (A) W = 500 J, △U = 0
• (B) Q = 500J, W = 0
• (C) △U = -0.5 J, Q = -500 J
• (D) Q = -500 J, △U = 0

92. What is the work done when 2 mole of an ideal gas is expanded isothermally and reversiblty from 5m³ to 10 m³ at 300 K? (R = 8.314 J  K^-1 mol^-1)

• (A) -34.58 kJ
• (B) -3.458 kJ 
• (C) 3.458 kJ 
• (D) -1.725 kJ

93. The heat of combustion of acetaldehyde to carbon dioxide and water is -1172 kJ mol^-1 Calculate amount of heat liberated when 66 g of acetaldehyde were completely oxidized.(At. Mass C = 12, H = 1, O = 16) 

• (A) 1172 kJ 
• (B) 6600 kJ 
• (C) 2344 kJ
• (D) 1758 kJ

94. Which will be the reaction becomes spontaneous at all temperatures?

• (A) △H = +ve, △S = +ve, △G = -ve
• (B) △H = +ve, △S = -ve, △G = +ve
• (C) △H = -ve, △S = -ve, △G = -ve
• (D) △H = -ve, △S = +ve, △G = -ve

95. An ideal gas expands isothermally and reversibly from 10 m³ to 20 m³ at 300 K performing 5.187 kJ of work on surrounding. Calculate number of moles of gas undergoing expansion. (R = 8.314 J K^-1 mol^-1)

• (A) 2
• (B) 3 
• (C) 1.5 
• (D) 1 

96. If △H° and △S° for the reaction N2O4(g)  → 2NO2(g) is 57.24 kJ and 175.8 JK^-1 mol^-1 respectively. What is the value of △G° for this reaction at 298 K? 

• (A) 57.24 kJ 
• (B) -17.58 kJ 
• (C) 4.85 kJ 
• (D) -4.85 kJ

97. Which of the following is an extensive property? 

• (A) Density 
• (B) Surface tension 
• (C) Specific heat 
• (D) Volume 

98. For the reaction, C2H5OH(l) + 3O2(g) → 2CO2(g) +3H2O(l)

Which among the following is true? 

• (A) △H = △U + 2 RT 
• (B) △H = △U + RT 
• (C) △H = △U - 2 RT 
• (D) △H = △U - RT

99. Work done when 2 moles of an ideal gas is compressed from a volume of 5 m³ to 1 dm³ at 300K, under a pressure of 100 kPa is 

• (A) - 409.9 kJ 
• (B) - 99.5 kJ 
• (C) 424.95 kJ 
• (D) 499.9 kJ 

100. In which of the following reactions, △H is not equal to △U ? 

• (A) SO2(g) + NO2(g) → SO3(g) + NO(g)
• (B) N2(g) + O2(g) → 2NO(g) 
• (C) H2(g) +I2(g) → 2HI(g) 
• (D) 2SO2(g) + O2(g) → 2SO3(g)

101. If heat of combustion of methane is -800 kJ mo1^-1, calculate enthalpy change for combustion of 4 x 10^-4 kg of methane. 

• (A) -800 kJ 
• (B) -3.2 x 10^4 kJ 
• (C) -280 kJ 
• (D) -20 kJ 

102. Thermodynamics deals with 

• (A) microscopic properties of system 
• (B) macroscopic properties of the. system 
• (C) rates at which physical and chemical processes occur 
• (D) the path between the two states of the system 

103. Which of the following set of parameters indicte spontaneity of reaction at all temperatures? 

• (A) △H = +ve, △S = +ve, △G = -ve 
• (B) △H = + ve, △S = -ve, △G = +ve 
• (C) △H = -ve, △S = +ve, △G = -ve 
• (D) △H = -ve, △S = -ve, △G = + ve 

104.The standard entropies of N2(g), H2(g) and NH3(g) are 191.5, 130.5 and 192.6 J K^-1mol^-1 respectively. The values of △S° for formation of NH3(g), is 

• (A) - 98.9 J K^-1 mol^-1 
• (B) Zero 
• (C) 129.4 J K^-1 mol^-1 
• (D) - 29.4 J K^-1 mol^-1 

105. For an isothermal process 

• (A) Q < W 
• (B) Q = -W 
• (C) Q = W 
• (D) Q > W

106. Heat of formation of water is - 272 kJ mol^-1. What quantity of water is converted to H2 and O2 by 750 kJ of heat? 

• (A) 7.5 mol 
• (B) 2.75 mol 
• (C) 5.5 mol 
• (D) 0.275 mol

107. At what temperature, a chemical reaction will have following values of △G, △S and △H ? △G = -5.2 KJ mol^-1, △H = 145.6 kJ mol^-1, △S = -216 kJ mol^-1 

• (A) 698.1 K 
• (B) 650.0 K 
• (C) 823.0 K 
• (D) 425.0 K

108. Heat of formation of ethane, ethylene acetylene and carbon dioxide are -136, -66, -228 and -395 (all in kJ) respectively, most stable among them is

• (A) Carbon dioxide 
• (B) Acetylene 
• (C) Ethylene 
• (D) Ethane

109. Which of following is residual entropy of a substance? 

• (A) entropy of solid equal to 0 at T = 0 
• (B) entropy of solid equal to 0 at T = 273 K
• (C) entropy of solid greater than 0 at T = 273 K
• (D) entropy of solid greater than 0 at T = 0 K

110. For a reaction △H = -50 kJ, △S = -150J K^-1 at 400 K. What is the value of △G?

• (A) +10 kJ
• (B) -110 kJ 
• (C) -10 kJ 
• (D) -50.15 kJ

111. From the following reaction, calculate the amount of heat liberated during formation of 75 g ethane.

    C2H4(g) + H2(g) → C2H6(g); △H = -124 kJ mol^-1 (At mass C = 12, H = 1)

• (A) 248 kJ
• (B) 310 kJ 
• (C) 372 kJ 
• (D) 284 kJ 

 112. Which of the following reactions is NOT exothermic? 

• (A) H2(g) + 1/2O2(g) → H2O(l) + 286 kJ
• (B) 2KClO3(s) → 2KCI(s) + 3O2(g) + 78 kJ 
• (C) N2(g) + 2O2(g) → 2NO2(g) - 66.4 kJ 
• (D) CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + 890 kJ
  

113. For combustion of 1 mole of liquid benzene at 298 K. the heat of reaction at constant volume is -3264.2 kJ. What is the heat of combustion at constant pressure? (R = 8.314 J K^-1 mol^-1)

• (A) -3267.9 kJ mol^-1 
• (B) -816.9 kJ mor^-1 
• (C) -2439.2 kJ mo^-1
• (D) -1633.9 kJ mol^-1

114. Standard entropies of N2(g), H2(g) and NH4(g) are al, a2 and a3 J K^-1 mol^-1 respectively. What is value of △S for formation of NH3(g)

• (A) a3 -1/2a1  + 3/2a2
• (B) a3 -(1/2 a1 + 3/2a2) 
• (C) a2 -(1/2a1 + 3/2a2)
• (D) a1 -(1/2a3 + 3/2a2)

115. If 200mL of ethylene gas and 200 mL of HCI gas are allowed to react at 2 atmosphere pressure as per given reaction, 

    C2H4(g) + HCl → C2H5Cl(g)

Calculate pressure volume work in Joule. 

• (A) 20.26 J
• (B) 54.40 J
• (C) 40.52 J
• (D) 26.20 J

116. How many gram of water is decomposed by 429 kJ of heat if heat of decomposition of water is 286 kJ mol^-1 ? 

• (A) 27 g
• (B) 40 g
• (C) 36 g
• (D) 22.5 g

117. Identify endothermic reaction from following

• (A) 2KClO3(s) →2KCl(s) + 3O2(g) + 78 kJ
• (B) N2(g) + 2O(g) →2NO2(g) - 66.4 kJ
• (C) CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + 890 kJ
• (D) H2(g) + 1/2O2(g) → H2O(l) + 286 kJ

118. At ehat temperature, a chemical reaction will have following values?

△G = 4 kJ, △H = -60 kJ, △S = -160 J

• (A) 300 K
• (B) 250 K
• (C) 350 K
• (D) 400 K

119. Standard molar entropy is 

• (A) the absolute entropy of one mole of a pure substance at 1 atm and 25 °C
• (B) the absolute entropy of one mole of a pure substance at 1 atm and 298 °C 
• (C) the absolute erampy of one mole of a pure substance at 700 mm pressure and 25 °C
• (D) the absotute entropy of one gram of a pure substance at 1 atm and 298 °C

120. Three mole of an ideal gas expand isothermally and reversibly from 10 m³ to 20 m³ at 300 K, calculate the work done. (R = 8.314 J K^-1 mol^-1)

• (A) -1037.4 kJ
• (B) -2593.5 kJ 
• (C) -51.87 kJ
• (D) -5.187 kJ

121. A system releases 15 kJ of energy as heat and does 10 kJ work on surrounding, calculate internal energy change. 

• (A) 5kJ 
• (B) - 5kJ
• (C) -25 kJ
• (D) 25 kJ

122.Calculaic the amount of heat liberated during formation of 2.7 kg of water if heat of formation of water is - 284.5 kJ mol^-1

• (A) 4.267 x. 10^4 kJ
• (B) 4.267 x 10³ kJ 
• (C) 1.896 x 10^4 kJ
• (D) 2.896 x 10³ kJ

123. For which of the following reaction, △H = △U?

• (A) 2CO(g) + O2 → 2CO2(g)
• (B) H2O(l) △ H2O(g)
• (C) H2(g) + Br(g) → 2HBr(g)
• (D) PCl5(g) → PCl3(g) + Cl2(g)

124. Which of the following equations shows the relationship between heat of reaction at constant pressure and heat of reaction at constant volume if the temperature is not constant? 

• (A) △H - △n = △URT
• (B) △H = △U - RT
• (C) △H = △nRT 
• (D) △H - △U = △nRT

125. If C(g) + O2(g) → CO2(g),  △H= -396 kJ mol^-1, calculate heat liberated during formation of 0.154 kg of CO2.

• (A) 1386.0 kJ
• (B) 346.5 kJ 
• (C) 693.0 kJ 
• (D) 1039.5 kJ

126. The H-H bond energy is 430 kJ mol^-1 and CI-CI bond energy is 240 kJ mol^-1. △H for HCl is - 90 kJ. then H-C1 bond energy is

• (A) 213 kJ mol^-1
• (B) 180 kJ mol^-1
• (C) 360 kJ mol^-1
• (D) 425 kJ mol^-1

127. Heat of combustion of liquid benzene to carbon dioxide and water is -3266 kJ mol^-1, What is the amount of heat liberated when 780 mg of benzene is fully oxidised? (At mass of C = 12, H = 1) 

• (A) 65.32 kJ 
• (B) 326.6 kJ 
• (C) 16.33 kJ 
• (D) 32.66 kJ 

.128. Which of the following is an intensive property? 

• (A) Internal energy 
• (B) Mass 
• (C) Volume
• (D) Melting point

129. When will be change in Gibb's free energy always negative? 

• (A) △H and △S both positive at low temperature. 
• (B) △H = negative, △S = positive, at all temperatures.
• (C) △H = positive, △S = negative at all temperatures. 
• (D) △H and △S both negative at high temperature.

130. Heat of formation of SO2 is -298 kJ mol^-1. Calculate enthalpy change during formation of 4 g of SO2.

• (A) -32.8 kJ
• (B) -18.6 kJ 
• (C) -37 kJ 
• (D) -20.4 kJ 

131. identify the unit used for measurement of energy according to international system of units? 

• (A) J K^-1 mol^-1
• (B) kg m² s^-2 
• (C) kg m^-1 s^-2 
• (D) kg m^-2 s² 

132. The equilibrium constant for a reaction is 10, value of △G° at 300 K is (R = 8 x 10^-3 kJ)

• (A) 11.054 kJ mo1^-1
• (B) 2.763 kJ mo1^-1 
• (C) 5.527 kJ mol^-1 
• (D) -5.527 kJ mol^-1 

133. Heat of formation of H2O is -270 kJ mol^-1. How much water can be decomposed by 675 kJ of heat? 

• (A) 45 g 
• (B) 33 g 
• (C) 40 g 
• (D) 27 g 

134. When will be the reaction becomes spontaneous at all temperatures? 

• (A) △H = +ve or -ve, △S = 0, △G = 0
• (B) △H = -ve, △S = +ve, △G = -ve 
• (C) △H = +ve, △S = -ve, △G = +ve 
• (D) △H = -ve, △S = -ve, △G = -ve or +ve

135. A sample of gas absorbs 4000 kJ of heat and surrounding does 2000 J of work on sample, what is the value of △U ? 

• (A) 4000 kJ 
• (B) 6000 kJ 
• (C) 2000 kJ 
• (D) 4002 kJ

136. Which of the following statements does not represent first law of thermodynamics? 

• (A) The spontaneous flow of heat is always unidirectional from high to low temperature. 
• (B) The total internal energy of an isolated system is constant. 
• (C) Total energy of universe is constant. 
• (D) When one form of energy disappears, exactly equivalent amount of other form must appear. 

137. Given that, 

C(s) + O2(g) → CO2(g) , △H° = -X kJ ,

2CO(g) + O2(g) → 2CO2(g) △H° = -Y kJ. then standard enthalpy of formation of carbon monoxide is

• (A) Y - 2X kJ 
• (B) 2X - Y kJ
• (C) (Y - 2X)/2 kJ
• (D) (2X - Y)/2 kJ

138. 2.5 kJ of work is done on the system and it releases 1500 J of heat. What is the change in internal energy? 

• (A) 4000 J 
• (B) 1000 J
• (C) 1500 J 
• (D) 2500 J