PHYSICAL CHEMISTRY by: SHAILENDRA KR. Classes at: - SCIENCE TUTORIALS; Opp. Khuda Baksh Library, Ashok Rajpath, Patna PIN POINT STUDY CIRCLE; House No. 5A/65, Opp. Mahual Kothi, Alpana Market, Patna Topic: Thermodynamics Meq. Approach 1. The efficiency of heat engine is miximum when a) Temperature of source > temperature of sink b) Temperature of sink > temperature of source c) Temperature difference of source and sink is minimum d) Temperature difference of source and sink is maximum 2. Entopy change of vaporisation at constant pressure is given by : a) S v) = H v /T b) S v) = E v /T b) S v) = H v / T 3. Entropy change of fusion at constant pressure is given by : a) S f) = H f /T b) S f) = G f /T c) S f) = H f / T 4. Change is entropy for a reaction is given by : a) 2.303 nr log 10 V 2 b) nr log e V 2 c) nr log e P 1 /P 2 d) All 5. Work done in reversible adiabatic process is given by : a) 2.303 RT log V 2 b) nr /γ 1) T 2 T 1 ) c) 2.303 RT log V 1 /V 2 6. Work done in reversible isothermal process is given by : a) 2.303 RT log V 2 b)nr /γ 1)T 2 T 1 ) c) 2.303 RT log V 1 /V 2 7. The heat measured for a reaction in a bomb calorimeter is : a) G b) H c) E d) P V 8. The internal energy of one mole of a gas is : a) 3/2RT b) KT/2 c) RT/2 d) 3KT/2 9. Internal energy and pressure of a gas of unit volume are related as : a) P = 2/3E b) P = 3/2E c) P = E/2 d) P = 2E 10. A closed flask contains water in all its three states, solides, liquid and vapour at 0 C. In this situation the average KE of the water molecule will be : a) Maximum in vapour state b) Maximum in solid state c) Greater in the liquid than in vapour state d) Same in all the three states 11. At constant pressure and temperature. The direction of any chemical reaction is one where, the...decrease : a) Entropy b) Enthalpy c) Gibbs free energy 12. Human body is an example of : a) Open system b) Closed system c) Isolated system 13. When ice malts into water, entropy : a) Becomes zero b) Decreases c) Increases d) Remains the same 14. Equilibrium constant of a reaction is related to a) Standard free energy change G b) Free energy change G c) Heat enthalpy Page No.: 1
15. Which has the least entropy : a) Graphite b) Diamond c) N 2 g) d) N 2 Og) 16. Which is not a spontaneous process : a) Expansion of a gas into vacuum b) Water flowing down hill c) Heat flowing from colder body to a hotter body d) Evaporation of water from clothes during drying 17. When the value of entropy is greater, then the ability for work is : a) Maximum b) minimum c) Medium of these 18. The total entropy change for a system and its surrounding increase, if the process is : a) Reversible b) Irreversible c) Exothermic d) Endothermic 19. In a reversible isothermal process, the change in internal energy is : a) Zero b) Positive c) Negative 20. The matter has highest entropy in : a) Solid state b) Liquid state c) Gaseous state d) Equal in all 21. Least random state of water is : a) Ice b) Liquid water c) Steam d) All present in same random state 22. When a solid is changed into liquid the entropy a) Decreases b) Increases c) Remains constant 23. During an isothermal expansion of an ideal gas its : a) Enthalpy decreases b) Internal energy decreases c) Internal energy increases d) Internal energy remains constant 24. During isothermal transformation of an ideal gas, internal energy : a) Increases as the pressure increases b) Decreases as the volume decreases c) Decreases as the pressure decreases d) Remains fixed 25. Work done by the system on surrounding is : a) Positive b) Negative c) Zero 26. A gaseous system changes from state AP 1, V 1, T 1 ) to B P 2, V 2, T 2 ) B to C P 3, V 3, T 3 ) and finally from C to A. The whole process may be called : a) Reversible process b) Cyclic process c) Isobaric process d) Spontaneous process 27. If temperature remains constant during a reaction the process is called : a) Isothermal b) Isochoric c) Isobaric d) Adiabatic 28. During an adiabatic process : a) Pressure is maintained constant b) Gas is isothermally expanded c) There is perfect heat insulation d) The system changes heat with surroundings 29. Highest entropy is in : a) Water b) Hydrogen c) Mercury d) Graphite 30. If G > 0, for a reaction then : a) K p > 1 b) K p < 1 c) The products predominate in the equilibrium mixture 31. The cooling in refrigerator is due to : a) The work of compressor b) The expansion of gas in the refrigerator c) Expansion of ice d) Reaction of the refrogerator gas 32. A thermodynamic state function is : a) One which obeys all the laws of thermodynamics b) A quantity which is used to measure thermal changes c) A quantity whose value is independent of the path d) A quantity which is used to express pressure-volume work Page No.: 2
33. A system is changed from state A to state B by one path and from B to A by another path. If E 1 and E 2 are the corresponding changes in internal energy, then : a) E 1 + E 2 = + ve b) E 1 + E 2 = ve c) E 1 + E 2 = 0 34. Temperature and heat are : a) Extensive properties b) Intensive properties c) Intensive and extensive properties respectively d) Extensive and intensive properties respectively 35. A gas expands isothermally and reversibly. The work done by the gas is : a) Zero b) Minimum c) Maximum d) Equal to work done 36. In an isothermal expansion of an ideal gas : a) Q = 0 b) V = 0 c) W = 0 d) E = 0 37. If a refrigerator door is kept open, then we get : a) Room cooled b) Room heated c) More heat is passed out d) No effect on room 38. In a spontaneous irreversible process, the total entropy of the system and surroundings : a) Remains constant b) Increases c) Decreases d) Zero 39. S is positive for the change : a) Mixing of two gases b) Boiling of liquid c) Melting of solid d) All 40. Joule Thomson coefficient for ideal gas is : a) Zero b) Positive c) Negative d) Infinite 41. When hydrogen and oxygen burn to form water in an oxyhydrogen torch, the entropy change is : a) Negative b) Positive c) zero d) May be positive or negative 42. On dissolving NaCl in water there occurs : a) Increase in free energy b) Increase in entropy c) Decrease in entropy d) No change in entropy 43. Which gas shows a heating effect when expanded into a region of low pressure: a) O 2 b) NH 3 c) N 2 d) H 2 44. For the precipitation of AgCl by Ag + ions and HCl: a) H = 0 b) G = 0 c) G = ve d) H = G 45. Gibbs free energy G, enthalpy H and entropy S are related by: a) G = H + TS b) G = H TS c) G TS = H d) S = H G 46. The total amount of energy in the universe is fixed, but: a) Matter is increasing b) Gravitation is decreasing c) Disorder is increasing d) Lightening is increasing 47. For the reversible vaporisation of water at 100 C and 1 atmospheric pressure, G is equal to: a) H b) S c) Zero d) H/T 48. Entropy is a measure of disorder. For perfect crystalline substances at 0 K, entropy becomes: a) Minus b) Zero c) Constant d) Very low 49. Which statements are correct: P 2 H vap. [T 2 T 1 ] a) 2.303 log P = is 1 R T 1 T 2 Clausius-Clapeyronequation H vap. b) boiling point = 88 J mol 1 K 1 is called Trouton s rule c) Entropy is a measure of uavailable energy i.e.; unvailable energy = entropy temprerature d) all Page No.: 3
50. It is impossible to attain the lowest temperature known as zero degree absolute. This is a simple statement of: a) First law of thermodynamics b) Second law of thermodynamics c) Third law of thermodynamics 51. An ideal gas undergoing expansion in vaccum shows: a) E = 0 b) W = 0 d) q = 0 d) All 52. An example of closed system is: a) Hot water present in an open beaker b) Some amount of water present in equilibrium with its vapour in a closed and insulated beaker c) Some amount of hot water enclosed in a closed container which is not insulated 53. Decrease in free energy of a reactiong system indicates to: a) Exothermic reaction b) Equilibrium reaction c) Spontaneous reaction d) Slow reaction 54. For the reaction having H and S both positive, the rate of reaction: a) Increases with the increase in temperature b) Decreases with the increase in temperature c) Has no effect of temprature d) Decreases with the increase in pressure 55. 1 litre-atmosphere is equal to: a) 101.3 J b) 24.206 cal c) 101.3 10 7 erg d) All 56. The van t Hoff reaction isotherm is: a) G = RT log e K p b) G= RT log e K p c) G = RT 2 In K p 57. The temperature of the system increases during an: a) Isothermal expansion. b) Adiabatic compression c) Adiabatic expansion d) Isothermal compression 58. The entropy change at a given temperature is expressed as: a) S = q T b) S = q/ T c) q = T S d) S = q/t 59. In an irreversible process, the value of S system + S surr. is: a) > 0 b) < 0 c) = 0 d) All 60. Which statements is are correct: δh δe a) δt p δt v = R δh δe b) > δt p δt v δe c) for ideal gas is zero δv v d) All 61. A thrmodynamic quantity is that: a) Which is used in thermochenistry b) Which obeys all the law of thermodynamics c) Quantity which depends only on the state of the system d) Quantity which is used in measuring thermal change 62. The process in which pressure remains constant throughout a change is : a) Adiabatic b) Isochoric c) Isobaric d) Isothermal 63. Which one is not a spontaneous process : a) Dissolution of CuSO 4 in water b) Water flowing down the hills c) Flow of current from low potential to high potential 64. Internal energy of a system containing molecules is reported as : a) Kinetic energy b) Vibrational energy c) Rotational energy d) All kinds of energy associated with it 65. A gas on subjecting to adiabatic expansion gets cooled due to : a) Fall in temperature b) Loss of kinetic energy Page No.: 4
c) Decrease in velocity d) Energy used in doing work 66. When two atoms hydrogen combine to form a molecule of hydrogen gas, the energy of the molecule is : a) Greater than that of separate atoms b) Equal to that of separate atoms c) Lower than that of separate atoms d) Sometimes lower and something higher 67. For which process energy will be absorbed : a) Separation of an electron from an electron b) Separation of an proton from a proton c) Separation of a neutron from neutron d) Separation of an electron from a neutral atom 68. Which of the following have same units : i) Work ii) Heat iii) Energy iv) Entropy a) i), ii) and iii) b) i), ii) and iv) c) ii), iii) and iv) d) iii) and iv) 69. Select the correct limitations of III law of thermodynamics : a) Glass solids at zero Kelvin has entropy greater than zero b) Solides having mixtures of isotopes do not have entropy zero at zero Kelvin c) Crystals of CO, N 2 O, NO, H 2 O, etc., do not have Zero entropy at zero Kelvin d) All 70. Which are correct to express work terms : a) Work = Capacity factor Intencity factor; where capacity factor is a measure of extent of work done and intensity factor is a measure of force responsible for work b) Electrical work = E nf ; E is intensity factor; nf is capacity factor c) Expansion work = P V; P is intensity factor ; V is capacity factor d) All 71. For the process, melting of ice at 260 K, the H is : a) Negative b) Positive c) Zero d) Cannot be predicted 72. The gas in a refrigerator cause cooling on expension because : a) Work done by the gas is converted into heat b) Heat of the gas is lost as work is done by the gas c) The heat is spread over a large space 73. The second law of thermodynamics introduced the concept of a) Third law of thermodynamics b) Work c) Entropy d) Internal energy 74. All the naturally occuring processes i.e., spontaneous proceed spontaneously in a direction which leads to : a) Decrease of free energy b) Increase of free energy c) Decrease of entropy d) Increase of enthalpy 75. A reaction taking place with absorption of energy is : a) Burning of a candle b) Electrolysis of water c) Digestion of food d) Rusting of iron 76. Vibrational energy is : a) Partially potential and partially kinetic b) Only potential c) Only kinetic 77. The heat change in a chemical reaction at constant pressure is : a) H b) E c) T d) V Page No.: 5
A N S W E R S 1. d 16. c 31. b 46. c 2. a 17. a 32. c 47. c 3. a 18. b 33. a 48. b 4. d 19. a 34. c 49. d 5. b 20. c 35. c 50. c 6. a 21. a 36. d 51. d 7. c 22. b 37. b 52. c 8. a 23. d 38. b 53. c 9. a 24. d 39. d 54. a 10. d 25. b 40. a 55. d 11. c 26. b 41. a 56. b 12. b 27. a 42. b 57. b 13. c 28. c 43. d 58. c 14. a 29. b 44. c 59. a 15. b 30. b 45. b 60. d 61. c 77. a 62. c 63. c 64. d 65. d 66. c 67. d 68. a 69. d 70. d 71. b 72. b 73. c 74. a 75. 1. b Opp. Khuda Baksh Library, Ashok Rajpath, Patna - 4 2. 76. House a no. 5A/65, Opp. Mahual Kothi, Alpana Market, Patna Page No.: 6