Thermodynamics PYQs Set 4 (PDF)

Set 4 of 14 · Questions 91-120 of 393

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Mere Teacher · Previous Year Questions NEET Chemistry · Thermodynamics · Set 4 (Q91-120)
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91. $The work done when two moles of an ideal gas is compressed from a volume of 5 m^{3} to 1 dm^{3} at 300 K, under a pressure of 100 kPa is$ (1) $499.9 kJ$ (2) $- 499.9 kJ$ (3) $- 99.5 kJ$ (4) $42495 kJ$ 92. $The enthalpy of formation of ammonia when calculated from the following bond energy data is (B.E. of N - H, H - H, N \equiv N is 389 kJ , 389 k J m o l^{- 1}, 435 k J m o l^{- 1}, 945.36 k J m o l^{- 1} respectively)$ (1) $- 41.82 k J m o l^{- 1}$ (2) $+ 83.64 k J m o l^{- 1}$ (3) $- 945.36 k J m o l^{- 1}$ (4) $- 833 k J m o l^{- 1}$ 93. $Identify an extensive property amongst the following.$ (1) $Viscosity$ (2) $Heat capacity$ (3) $Density$ (4) $Surface tension$ 94. $For the reaction, C_{3} H_{8 (g)} + 5 O_{2 (g)} \to 3 C O_{2 (g)} + 4 H_{2} O_{(l)} at constant temperature, Δ H - Δ E is$ (1) $+RTv$ (2) $-3RT$ (3) $+3RT$ (4) $-RT$ 95. $Given that bond energies of H - H and Cl —Cl are 430 kJmo l^{- 1} and 240 kJmo l^{- 1} respectively and Δ H_{f} for HC1 is - 90 kJmo l^{- 1}, bond enthalpy of HC1 is$ (1) $380 kJmo l^{- 1}$ (2) $425 kJmo l^{- 1}$ (3) $245 kJmo l^{- 1}$ (4) $290 kJmo l^{- 1}$ 96. $For a sample of perfect gas when its pressure is changed isothermally from p_{i} to p_{f}, the entropy change is given by$ (1) $Δ S = nR ln (\frac{p _{f}}{p _{i}})$ (2) $Δ S = nR ln (\frac{p _{i}}{p _{f}})$ (3) $Δ S = nRT ln (\frac{p _{f}}{p _{i}}) (d) Δ S = RT ln (\frac{p _{i}}{p _{f}})$ 97. $If a chemical reaction is known to be non-spontaneous at 298 K but spontaneous at 350 K, then which among the following conditions is true for the reaction?$ (1) $Δ G = - ve, Δ H = - ve, Δ S = + ve$ (2) $Δ G = + ve, Δ H = + ve, Δ S = + ve$ (3) $Δ G = - ve, Δ H = + ve, Δ S = + ve$ (4) $Δ G = + ve, Δ H = + ve, Δ S = - ve$ 98. $The enthalpies of formation of gaseous N_{2} O and NO at 298 K are 82.0 and 90.0 KJ mol^{- 1} respectively. The enthalpy change of the reaction N_{2} O (g) + \frac{1}{2} O_{2} (g) \to 2 NO (g) is$ (1) $- 74 kJ$ (2) $+ 98 kJ$ (3) $+ 89 kJ$ (4) $- 47 kJ$ 99. $For a given reaction, Δ H = 35.5 kJmo l^{- 1} and Δ S = 83.6 J K^{- 1} mo l^{- 1} . The reaction is spontaneous at (Assume that Δ H and Δ S do not vary with temperature.)$ (1) $T > 425 K$ (2) $all temperatures$ (3) $T > 298 K$ (4) $T < 425 K$ 100. $The INCORRECT match in the following is :$ (1) $Δ G^{0} < 0, K > 1$ (2) $Δ G^{0} = 0, K = 1$ (3) $Δ G^{0} > 0, K < 1$ (4) $Δ G^{0} < 0, K < 1$ 101. $Calculate the difference between heat of combustion of carbon monoxide gas at constant pressure and at constant volume at 27^{\circ} C ? (R = 2 cal K^{- 1} mol^{- 1})$ (1) $54 cal$ (2) $- 600 cal$ (3) $- 300 cal$ (4) $27 cal$ 102. $In a closed insulated container, a liquid is stirred with a paddle to increase its temperature. In this process, which of the following is true$ (1) $∆ E = W = Q = 0$ (2) $∆ E \neq = 0, Q = W = 0$ (3) $∆ E = W \neq = 0, Q = 0$ (4) $∆ E = Q \neq = 0, W = 0$ 103. $Identify the equation in which change in enthalpy is equal to change in internal energy.$ (1) $2 H_{2} O_{2 (l)} \to 2 H_{2} O_{(l)} + O_{2 (g)}$ (2) $C_{(s)} + O_{2 (g)} \to CO_{2 (g)}$ (3) $PCl_{5 (g)} \to PCl_{3 (g)} + Cl_{2 (g)}$ (4) $N_{2 (g)} + 3 H_{2 (g)} \to 2 NH_{3 (g)}$ 104. $9.0 gm of H_{2} O is vaporised at 100^{\circ} C and 1 atm pressure. If the latent heat of vaporisation of water is x J / gm, then Δ S is given by$ (1) $\frac{x}{373}$ (2) $\frac{18 x}{100}$ (3) $\frac{18 x}{373}$ (4) $\frac{1}{2} \times \frac{18 x}{373}$ 105. $The first and second ionisation enthalpies of a metal are 496 and 4560 kJ moll, respectively. How many moles of HCl and H_{2} S O_{4}, respectively, will be needed to react completely with 1 mole of the metal hydroxide?$ (1) $l and 0.5$ (2) $2 and 0.5$ (3) $1 and 2$ (4) $1 and 1$ 106. $Which law of thermodyanamics help in calculating entropy at different temperatures$ (1) $First law$ (2) $Second law$ (3) $Third law$ (4) $Zeroth law$ 107. $An irreversible process occuring isothermally in an isolated system leads to$ (1) $Zero entropy$ (2) $An increase in the total entropy of the system$ (3) $A decrease in the total entropy of the system$ (4) $None of these$ 108. $The process with negative entropy change is:$ (1) $Sublimation of dry ice$ (2) $Dissolution of iodine in water$ (3) $Dissociation of C a S O_{4} (s) to CaO(s) and S O_{3} (g)$ (4) $Synthesis of ammonia from N_{2} and H_{2}$ 109. $The difference between Δ H and Δ U (Δ H - Δ U) whenthe combustion of one mole of heptane (I) is carried out at a temperature T, is equal to:$ (1) $- 4 RT$ (2) $- 3 RT$ (3) $4 RT$ (4) $3 RT$ 110. $According to first law of thermodynamics, which of the following options is correct?$ (1) $Encrgy can be created only.$ (2) $Energy can be destroyed only.$ (3) $Energy can neither be created nor be destroyed.$ (4) $None of these.$ 111. $The equilibrium constant of a reaction is 0.008 at 298 K . The standard free energy change of the reaction at the same temperature is$ (1) $+ 11.96 kJ$ (2) $- 11.96 kJ$ (3) $- 5.43 kJ$ (4) $- 8.46 kJ$ 112. $If 2.5 moles of an ideal gas at a certain temperature are allowed to expand isothermally and reversibly from an initial volume of 2 dm^{3} to 20 dm^{3}, the work done by the gas is - 16.5 kJ . The temperature (in K) of the gas is (Round off to the nearest value) (R = 8.314 J K^{- 1} mol^{- 1})$ (1) $445$ (2) $245$ (3) $345$ (4) $745$ 113. $The work done to contract a gas in a cylinder, is 462 joules. 128 joule energy is evolved in the process. What will be the internal energy change in the process$ (1) $+ 590 joules$ (2) $- 334 joules$ (3) $+ 334 joules$ (4) $- 590 joules$ 114. $During isothermal expansion of an ideal gas, its$ (1) $internal energy increases$ (2) $enthalpy decreases$ (3) $enthalpy remains unaffected$ (4) $enthalpy reduces to zero.$ 115. $One mole of an ideal gas at 300 K in thermal contact with surroundings expands isothermally from 1.0 L to 2.0 L against a constant pressure of 3.0 atm. In this process, the change in entropy of surroundings (D S_{s u r r}) in J K^{-1} is: (1 L atm = 101.3 J)$ (1) $5.763$ (2) $1.013$ (3) $-1.013$ (4) $-5.763$ 116. $An air bag on adiabatic expansion undergoes 5 % increase in its volume. The percentage change in pressure is (γ_{air} = 1.4)$ (1) $5$ (2) $6$ (3) $7$ (4) $9$ 117. $What is the amount of work done when 0.5 mole of methane, CH_{4 (g)}, is subjected to combustion at 300 K ? (given, R = 8.314 JK^{- 1} mol^{- 1})$ (1) $- 2494 J$ (2) $- 4988 J$ (3) $+ 4988 J$ (4) $+ 2494 J$ 118. $If 92 gNa reacts with water in open vessel at 300 K . What is the value of work done? [Assume ideal nature of the gaseous product]$ (1) $0.0$ (2) $- 4988.4 J$ (3) $- 2494.2 J$ (4) $- 9976.8 J$ 119. $Which among the following reactions exhibits Δ H = Δ U ?$ (1) $H_{2 (g)} + Br_{2 (g)} ⟶ 2 HBr_{(g)}$ (2) $2 CO_{(g)} + O_{2 (g)} ⟶ 2 CO_{2 (g)}$ (3) $PCl_{5 (g)} ⟶ PCl_{3 (g)} + Cl_{2 (g)}$ (4) $C_{(s)} + 2 H_{2} O_{(g)} ⟶ 2 H_{2 (g)} + CO_{2 (g)}$ 120. $If a refrigerator's door is opened, then we get$ (1) $Room heated$ (2) $Room cooled$ (3) $More amount of heat is passed out$ (4) $No effect on room$