Thermodynamics PYQs Set 16 (PDF)

Set 16 of 18 · Questions 451-480 of 511

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Thermodynamics · Set 16 (Q451-480)
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451. $The entropy of a perfectly crystalline solid at absolute zero is$ (1) $Positive$ (2) $Negative$ (3) $Zero$ (4) $Not definite$ 452. $200 joules of heat was supplied to a system at constant volume. It resulted in the increase in temperature of the system from 298 to 323 K. what is the change in internal energy of the sytem?$ (1) $400 J$ (2) $200 J$ (3) $50 J$ (4) $150 J$ 453. $When the value of entropy is greater, then the ability of work$ (1) $Is maximum$ (2) $Is minimum$ (3) $Is medium$ (4) $None of these$ 454. $Which one among the following is the correct option for right relationship between C_{p} and C_{v} for one mole of ideal gas?$ (1) $C_{P} - C_{V} = R$ (2) $C_{p} = RC_{V}$ (3) $C_{v} = R C_{p}$ (4) $C_{p} + C_{v} = R$ 455. $At absolute zero, the entropy of a pure crystal is zero. This is.$ (1) $First law of thermodynamics$ (2) $Second law of thermodynamics$ (3) $Third law of thermodynamics$ (4) $Zeroth law of thermodynamics$ 456. $Identify the reaction/process in which the entropy decreases$ (1) $H_{2} O (l) \to H_{2} O (s)$ (2) $H_{2} O (l) \to H_{2} O (g)$ (3) $H_{2} O (g) \to 2 H (g)$ (4) $Crystal (100 K) \to Crystal (200 K)$ 457. $An ideal gas undergoes isothermal compression from 5 m^{3} to 1 m^{3} against a constant external pressure of 4 N m^{-2} . Heat released in this process is used to increase the temperature of 1 mole of Al. If molar heat capacity of Al is 24 J m o l^{-1} K^{-1}, the temperature of Al increases by:$ (1) $\frac{3}{2} K$ (2) $\frac{2}{3} K$ (3) $1 K$ (4) $2 K$ 458. $Arrange the following in order of magnitude of work done by the system/on the system at constant temperature. (i) (w_{reversible}) for expansion in infinite stages. (ii) (w_{irreversible}) for expansion in single stage. (iii) (w_{reversible}) for compression in infinite stages. (iv) (w_{irreversible}) for compression in single stage. Choose the correct answer from the options given below:$ (1) $iv > iii = i > ii$ (2) $iii = i > iv > ii$ (3) $i > iii > ii > iv$ (4) $i > ii > iii > iv$ 459. $For the following reaction : C a C O_{3} (s) ¾® CaO (s) + C O_{2} (g) If at 0K, DS for the reaction is x cal/mol then entropy of C O_{2} (g) at 0K is:$ (1) $- x cal$ (2) $- 2x cal$ (3) $+ x cal$ (4) $0 cal$ 460. $The standard enthalpy of formation of CO_{2} (g), CaO (s) and CaCO_{3} (s) are - 393, - 634, - 1210 kJ mol^{- 1} respectively. If all the substances are in standard state, the standard enthalpy of decomposition of calcium carbonate to CaO (s) and CO_{2} (g) (in kJ mol^{- 1}) is$ (1) $969$ (2) $183$ (3) $-969$ (4) $-183$ 461. $In a spontaneous process, the entropy of the system and its surroundings$ (1) $Equals zero$ (2) $Decreases$ (3) $Increases$ (4) $Remains constant$ 462. $A container has hydrogen and oxygen mixture in ratio of 4 : 1 by weight, then$ (1) $Internal energy of the mixture decreases$ (2) $Internal energy of the mixture increases$ (3) $Entropy of the mixture increases$ (4) $Entropy of the mixture decreases$ 463. $During compression of a spring the work done is 10 kJ and 2 kJ escaped to the surroundings as heat. The change in internal energy, Δ U (in kJ) is:$ (1) $- 12$ (2) $- 8$ (3) $8$ (4) $-4$ 464. $The entropy values (in J K^{- 1} m o l^{- 1}) of H_{2 (g)} = 130.6, C l_{2 (g)} = 223.0 and H C l_{(g)} = 186.7 at 298 K and 1 atm pressure. Then entropy change for the reaction H_{2 (g)} + C l_{2 (g)} \to 2 H C l_{(g)} is$ (1) $+ 540.3$ (2) $+ 727.3$ (3) $- 166.9$ (4) $+ 19.8$ 465. $Standard entropy change for the above reaction is$ (1) $60.3 JK^{- 1} mol^{- 1}$ (2) $80.7 JK^{- 1} mol^{- 1}$ (3) $- 70 JK^{- 1} mol^{- 1}$ (4) $+ 10.7 JK^{- 1} mol^{- 1}$ 466. $One mole of an ideal diatomic gas (C_{v} = 5 cal) was transformed from initial 2 5^{0} C and 1 L to the state when temperature is 10 0^{0} C and volume 10 L. The entropy change of the process can be expressed as (R = 2 calories/mol/K)$ (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) $5 ln \frac{373}{298} + 2 ln \frac{1}{10}$ 467. $If 900 J / g of heat is exchanged at boiling point of water, then what is increase in entropy$ (1) $43.4 J/mole$ (2) $87.2 J/mole$ (3) $900 J/mole$ (4) $Zero$ 468. $If one mole of an ideal gas is expanded isothermally at 300 K until it’s volume is tripled, then change in entropy of gas is: (C_{p, m} = \frac{5}{2} R)$ (1) $Zero$ (2) $Infinity$ (3) $\frac{5}{2} R ln 3$ (4) $R ln 3$ 469. $According to the following diagram, A reduces C O_{2} when the temperature is :$ (1) $> 1400°C$ (2) $< 1400°C$ (3) $> 1200° C but < 1400° C$ (4) $< 1200°C$ 470. $Given ∆ rS0 = -266 and the listed [S_{m}^{0} values] calculate S0 for Fe_{3} O_{4} (s): 4 F e_{3} O_{4} (s) [..............] + O_{2} (g) [205] 6 F e_{2} O_{3} (s) [87]$ (1) $+111.1$ (2) $+122.4$ (3) $145.75$ (4) $248.25$ 471. $At 298K, the enthalpy of fusion of a solid (X) is 2.8 k J m o l^{- 1} and the enthalpy of vaporisation of the liquid (X) is 98.2 k J m o l^{- 1} . The enthalpy of sublimation of the substance (X) in k J m o l^{- 1} is (in nearest integer)$ 472. $The bond dissociation enthalpy of X_{2} Δ H_{bond} calculated from the given data is kJmol^{- 1} . (Nearest integer) M^{+} X^{-} (s) \to M^{+} (g) + X^{-} (g) Δ H_{lattice}^{} = 800 kJ mol^{- 1} M (s) \to M (g) Δ H_{sub}^{\circ} = 100 kJ mol^{- 1} M (g) \to M^{+} (g) + e^{-} (g) Δ H_{i} = 500 kJ mol^{- 1} X (g) + e^{-} (g) \to X^{-} (g) Δ H_{eg}^{} = - 300 kJ mol^{- 1} M (s) + \frac{1}{2} X_{2} (g) \to M^{+} X^{-} (s) Δ H_{f}^{\circ} = - 400 kJ mol^{- 1} [Given : M^{+} X^{-} is a pure ionic compound and X forms a diatomic molecule X_{2} in gaseous state]$ 473. $Resonance in X_{2} Y can be represented as The enthalpy of formation of X_{2} Y (X = X (g) + \frac{1}{2} Y = Y (g) \to X_{2} Y (g)) is 80 kJ mol^{- 1} . The magnitude of resonance energy of X_{2} Y is kJ mol^{- 1} (nearest integer value). Given: Bond energies of X \equiv X, X = X, Y = Y and X = Y are 940, 410, 500, and 602 kJmol^{- 1} respectively. valence X : 3, Y : 2$ 474. $When 2 litre of ideal gas expands isothermally into vacuum to a total volume of 6 litre, the change in internal energy is______J. (Nearest integer)$ 475. $Consider the figure provided. 1 mol of an ideal gas is kept in a cylinder, fitted with a piston, at the position A, at 18^{\circ} C . If the piston is moved to position B, keeping the temperature unchanged, then ' x' L atm work is done in this reversible process. x =________Latm . (nearest integer) [Given : Absolute temperature =^{\circ} C + 273.15, R = 0.08206 L atm mol^{- 1} K^{- 1}]$ 476. $An athlete is given 100 g of glucose (C_{6} H_{12} O_{6}) for energy. This is equivalent to 1800 kJ of energy. The 50% of this energy gained is utilized by the athlete for sports activities at the event. In order to avoid storage of energy, the weight of extra water he would need to perspire is_______g (Nearest integer) Assume that there is no other way of consuming stored energy. Given : The enthalpy of evaporation of water is 45 kJ m o l^{- 1} Molar mass of C, H & O are 12. 1 and 16 g m o l^{- 1} .$ 477. $The magnitude of work done by a gas that undergoes a reversible expansion along the path ABC shown in the figure is \dots\dots\dots\dots$ 478. $The heat of solution of anhydrous CuSO_{4} and CuSO_{4} \cdot 5 H_{2} O are - 70 kJ mol^{- 1} and + 12 kJ mol^{- 1} respectively. The heat of hydration of CuSO_{4} to CuSO_{4} \cdot 5 H_{2} O is - x kJ . The value of x is ______ (nearest integer).$ 479. $A system does 200J of work and at the same time absorbs 150J of heat. The magnitude of the change in internal energy is J. (Nearest integer)$ 480. $According to the following figure, the magnitude of the enthalpy change of the reaction A + B \to M+ N in kJ m o l^{- 1} is equal to ____. (Integer answer)$