Thermodynamics PYQs Set 13 (PDF)

Set 13 of 14 · Questions 361-390 of 393

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Mere Teacher · Previous Year Questions NEET Chemistry · Thermodynamics · Set 13 (Q361-390)
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361. $One mole of an ideal diatomic gas (C_{v} = 5 cal) was transformed from initial 2 5^{0} C and 1 L to the state when temperature is 10 0^{0} C and volume 10 L. The entropy change of the process can be expressed as (R = 2 calories/mol/K)$ (1) $3 ln \frac{298}{373} + 2 ln 10$ (2) $5 ln \frac{373}{298} + 2 ln 10$ (3) $7 ln \frac{373}{298} + 2 ln \frac{1}{10}$ (4) $5 ln \frac{373}{298} + 2 ln \frac{1}{10}$ 362. $If 900 J / g of heat is exchanged at boiling point of water, then what is increase in entropy$ (1) $43.4 J/mole$ (2) $87.2 J/mole$ (3) $900 J/mole$ (4) $Zero$ 363. $If one mole of an ideal gas is expanded isothermally at 300 K until it’s volume is tripled, then change in entropy of gas is: (C_{p, m} = \frac{5}{2} R)$ (1) $Zero$ (2) $Infinity$ (3) $\frac{5}{2} R ln 3$ (4) $R ln 3$ 364. $According to the following diagram, A reduces C O_{2} when the temperature is :$ (1) $> 1400°C$ (2) $< 1400°C$ (3) $> 1200° C but < 1400° C$ (4) $< 1200°C$ 365. $Given ∆ rS0 = -266 and the listed [S_{m}^{0} values] calculate S0 for Fe_{3} O_{4} (s): 4 F e_{3} O_{4} (s) [..............] + O_{2} (g) [205] 6 F e_{2} O_{3} (s) [87]$ (1) $+111.1$ (2) $+122.4$ (3) $145.75$ (4) $248.25$ 366. $For the process H_{2} O (l) (1 bar, 373 K) \to H_{2} O (g) (1 bar, 373 K), the correct set of thermodynamic parameters is :$ (1) $Δ G = 0, Δ S = + v e$ (2) $Δ G = 0, Δ S = - v e$ (3) $Δ G = + v e, Δ S = 0$ (4) $Δ G = - v e, Δ S = + v e$ 367. $Δ U equal to:$ (1) $Isobaric work$ (2) $Adiabatic work$ (3) $Isothermal work$ (4) $Isochoric work$ 368. $The spontaneous flow of heat is always$ (1) $From low to high pressure$ (2) $From high to high pressure$ (3) $Unidirectional from lower temperature to higher temperature$ (4) $Unidirectional from the higher to lower temperature$ 369. $The incorrect expression among the following is:$ (1) $\frac{Δ G _{sy s t e m}}{Δ S _{t o t a l}} = - T (at constant P)$ (2) $ln K = \frac{Δ H ^{0} - T Δ S ^{0}}{R T}$ (3) $K = e^{- Δ G^{0} / R T}$ (4) $For isothermal process W_{r e v er s ib l e} = - n R T ln \frac{V _{f}}{V _{i}}$ 370. $Two blocks of the same metal having same mass and at temperature T_{1} and T_{2}, respectively, are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy, Δ S, for this process is:$ (1) $2 C_{P} ln (\frac{T _{1} + T _{2}}{4 T _{1} T _{2}})$ (2) $2 C_{P} ln [\frac{( T _{1} + T _{2} ) ^{2}}{T _{1} T _{2}}]^{1/2}$ (3) $C_{P} ln [\frac{( T _{1} + T _{2} ) ^{2}}{4 T _{1} T _{2}}]$ (4) $2 C_{P} ln [\frac{T _{1} + T _{2}}{2 T _{1} T _{2}}]$ 371. $The bond energy (in kcal m o l^{-1}) of a C-C single bond is approximately :$ (1) $1$ (2) $10$ (3) $100$ (4) $1000$ 372. $Then entropy (Sº) of the following substances are: C H_{4} (g) 186.2 J K^{-1} m o l^{-1}, O_{2} (g) 205.0 J K^{-1} m o l^{-1} C O_{2} (g) 213.6 J K^{-1} m o l^{-1}, H_{2} O(l) 69.9 J K^{-1} m o l^{-1} The entropy change (DSº) for the reaction C H_{4} (g) + 2 O_{2} (g) ® C O_{2} (g) + 2 H_{2} O(l) is :$ (1) $-312.5 J K^{-1} m o l^{-1}$ (2) $-242.3 J K^{-1} m o l^{-1}$ (3) $-108.1 J K^{-1} m o l^{-1}$ (4) $-37.6 J K^{-1} m o l^{-1}$ 373. $When a solid is converted into liquid, entropy$ (1) $Becomes zero$ (2) $Remains the same$ (3) $Decreases$ (4) $Increases$ 374. $The standard enthalpy of formation (D_{f} H º_{298}) for methane, C H_{4} is -74.9 kJ m o l^{-1} . In order to calculate the average energy given out in the formation of a C-H bond from this it is necessary to know which one of the following?$ (1) $the dissocation energy of the hydrogen molecule, H_{2} .$ (2) $the first four ionisation energies of carbon.$ (3) $the dissociation energy of H_{2} and enthalpy of sublimation of carbon (graphite).$ (4) $the first four ionisation energies of carbon and electron affinity of hydrogen$ 375. $The correct statement regarding entropy is$ (1) $at absolute zero temperature, entropy of a perfectly crystalline solid is zero$ (2) $at absolute zero temperature, the entropy of a perfectly crystalline substance is + ve$ (3) $at absolute zero temperature, the entropy of all crystalline substances is zero$ (4) $at 0^{\circ} C, the entropy of a perfect crystalline solid is zero.$ 376. $Which of the following equations are correct?(A) U = H - PV (B) G = H - TS (C) U = q + W$ (1) $A, B and C$ (2) $A and B only$ (3) $A and C only$ (4) $B and C only$ 377. $Which of the following reactions is associated with the most negative change in entropy?$ (1) $2SO2 (g) + O2 (g) 2SO3 (g)$ (2) $C_{2} H_{4} (g) + H_{2} (g) C_{2} H_{6} (g)$ (3) $C (s, graphite) + O_{2} C O_{2} (g)$ (4) $3 C_{2} H_{2} (g) C_{6} H_{6} (ℓ)$ 378. $If the bond energies of H - H, Br - Br and H - Br are 433, 192 and 364 kl mol^{- 1} respectively, then Δ H^{\circ} for the reaction: H_{2 (g)} + Br_{2 (g)} ⟶ 2 HBr_{(g)} is$ (1) $- 261 kJ$ (2) $+ 103 k$ (3) $+ 261 kJ$ (4) $- 103 kJ$ 379. $The molar heat capacity (C_{p}) of C D_{2} O is 10 cals at 1000 K. The change in entropy associated with cooling of 32 g of C D_{2} O vapour from 1000 K to 100 K at constant pressure will be: (D = deuterium, at. mass = 2 u)$ (1) $23.03 cal d e g^{-1}$ (2) $- 23.03 cal d e g^{-1}$ (3) $2.303 cal d e g^{-1}$ (4) $- 2.303 cal d e g^{-1}$ 380. $Given R = 8.314 J K^{- 1} mol^{- 1}, the work done during combustion of 0.090 kg of ethane (molar mass = 30) at 300 K is$ (1) $- 18.7 kJ$ (2) $18.7 kJ$ (3) $6.234 kJ$ (4) $- 6.234 kJ$ 381. $Third law of thermodynamics states that:$ (1) $the entropy of a perfectly crystalline pure substance at zero K is zero.$ (2) $absolute entropy of hydrogen ion is zero at zero K.$ (3) $net change in entropy in conversion H_{2 (g)} (130 K) ® H_{2 (g)} (200K) is zero.$ (4) $entropy generally decrease in combustion reactions$ 382. $In which state, the matter have highest entropy$ (1) $Solid$ (2) $Liquid$ (3) $Gas$ (4) $Equal in all$ 383. $Which of the following statements is true?$ (1) $The total entropy of the universe remains constant.$ (2) $The total entropy of the universe is continuously decreasing.$ (3) $The total energy of the universe is continuously decreasing.$ (4) $The total energy of the universe remains constant.$ 384. $At T (K) 2 mole of an ideal gas is allowed to expand reversibly and isothermally from a pressure of 10 atmospheres to 1 atmosphere. The work done (in kJ) is (R = 8.3 J K^{- 1} mol^{- 1})$ (1) $- 3.82 \times 10^{- 1} \times T$ (2) $- 4.82 \times 10^{- 1} \times T$ (3) $- 2.82 \times 10^{- 2} \times T$ (4) $- 3.82 \times 10^{- 2} \times T$ 385. $At 373 K steam and water are in equilibrium and ∆ H = 40.98 k J m o l^{- 1} what will be ∆ S for conversion of water into steam?$ (1) $109.8 J K^{- 1} m o l^{- 1}$ (2) $31 J K^{- 1} m o l^{- 1}$ (3) $21.98 J K^{- 1} m o l^{- 1}$ (4) $326 J K^{- 1} m o l^{- 1}$ 386. $Among the following given substances, the one with zero Δ_{f} H^{\circ} is$ (1) $Diamond$ (2) $Graphite$ (3) $Fullerene$ (4) $Bituminous coal$ 387. $A reaction is at equilibrium at 10 0^{o} C and the enthalpy change for the reaction is 42.6 k J m o l^{- 1} What will be the value of ∆ S in J K^{- 1} m o l^{- 1 ?}$ (1) $120$ (2) $426.2$ (3) $373.1$ (4) $114.2$ 388. $Enthalpy change for the process H_{2} O(ice) ⇌ H_{2} O(water) is 6.01 k J m o l^{- 1} The entropy change of 1 mole of ice at its melting point will be.$ (1) $12 J K^{- 1} m o l^{- 1}$ (2) $22 J K^{- 1} m o l^{- 1}$ (3) $100 J K^{- 1} m o l^{- 1}$ (4) $30 J K^{- 1} m o l^{- 1}$ 389. $For a reaction: X \to Y + Z Absolute entropies are X = 120 J K^{- 1} m o l^{- 1}, Y = 213.8 J K^{- 1} m o l^{- 1} an d Z = 197.9 J K^{- 1} m o l^{- 1} will be the enetropy change at 298 K and 1 atm?$ (1) $291.7 J K^{- 1}$ (2) $255 J K^{- 1}$ (3) $213.8 J K^{- 1}$ (4) $257.3 J K^{- 1}$ 390. $Which of the following reactions will have the value of ∆ S with a negative sign?$ (1) $H_{2} O_{(l)} \to H_{2} O_{(g)}$ (2) $2 S O_{2 (g)} + O_{2 (g)} \to 2 S O_{3 (s)}$ (3) $C l_{2 (g)} \to 2 C l_{(g)}$ (4) $C a C O_{3 (s)} \to C a O_{(s)} + C O_{2 (g)}$