Title Chemical Thermodynamics - 02.pdf ✅

1 JEE ADVANCED 2024 Chemical Thermodynamics Single Correct (1 – 5) 1. The efficiency of the reversible heat engine is ηr and that of irreversible heat engine is ηi. Which of the following relation is correct? (1) ηr = η1 (2) ηr > η1 (3) ηr < η1 (4) η1 may be less than, greater than or equal to ηr, depending on the gas. 2. The standard molar entropy of an ideal gas (γ = 4 3 ) is 2.5cal/K-mol at 25∘C and 1 bar. The standard molar entropy of the gas at 323∘C and 1 bar is (ln 2 = 0.7) (1) undefined (2) 4R ln2 (3) 5.6cal/K-mol (4) 8.1cal/K-mol 3. The values of ΔG are very important in metallurgy. The ΔG values for the following reactions at 1000 K are given as follows. S2(s) + 2O2(g) → 2SO2(g); ΔG = −544 kJ 2Zn(s) + S2(s) → 2ZnS(s); ΔG = −293 kJ 2Zn(s) + O2(g) → 2ZnO(s); ΔG = −480 kJ The ΔG for the reaction 2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2(g) will be (1) −357 kJ (2) −731 kJ (3) −773 kJ (4) −229 kJ 4. An average human produces about 10 MJ of heat each day through metabolic activity. If a human body were an isolated system of mass 80 kg with the heat capacity of water, what temperature rise would the body experience? Heat capacity of water = 4.2 J/K-g. (1) 29.76°C (2) 2.976 K (3) 2.976 × 104 °C (4) 0.029°C 5. One mole of an ideal monoatomic gas is heated in a process PV 5/2 = constant. By what amount heat is absorbed in the process in 26°C rise in temperature? (1) 100 J (2) 180 J (3) 200 J (4) 208 J One or more than one correct 6. Select the correct option(s). (1) Molar internal energy is an intensive property. (2) Ideal gases produce more work in an isothermal reversible expansion as compared to Van der Waals gases, assuming (V >> nb). (3) Reversible process can be reversed at any point in the process by making infinitesimal change. (4) Less heat is absorbed by the gas in the reversible isothermal expansion as compared to irreversible isothermal expansion to the same final volume. 7. Which of the following statement(s) is/are true? (1) Cv,m is independent of temperature for a perfect gas. (2) If neither heat nor matter can enter or leave a system, the system must be isolated. (3) dF ∮d 0 F = , where F = U, H, G, S. (4) A process in which the final temperature equals to the initial temperature must be an isothermal process. 8. Which of the following statement(s) is/are incorrect? (1) ΔE = q + w for every thermodynamic system at rest in the absence of external field. (2) A thermodynamic process is specified by specifying the initial and final state of the system. (3) Adiabatic free expansion of any gas is also isothermal. (4) For every cyclic process, the final state of the surroundings is the same as the initial state of surroundings Comprehension: 1 As a result of the isobaric heating by ΔT = 72 K, one mole of a certain ideal gas obtains an amount of heat Q = 1.60 kJ. 9. The work performed by the gas is (1) 8.60 kJ (2) 0.60 kJ (3) 16.60 kJ (4) 4.60 kJ 10. The increment of its internal energy (in kJ) is (1) 1.0 (2) 1.6 (3) 2.2 (4) 2.0 DPP - 02
2 11. The value of γ for the gas is (1) 0.6 (2) 0.16 (3) 1.6 (4) 2.2 Integer Type Questions – Single Digit (0–9) 12. What amount of heat (in J) is to be transferred to nitrogen in the isobaric heating process for that gas to perform the work 2.0 J? 13. Ten moles of a certain ideal gas at a temperature 300 K was cooled isochorically so that the gas pressure reduced 2.0 times. Then, as a result of the isobaric process, the gas expanded till its temperature got back to the initial value. The total amount of heat (in Kcal) 14. The number of degrees of freedom of molecules in a gas whose molar heat capacity is 29 J/mol-K in the process PT = constant is Matrix – Match Type Questions 15. Match the columns. Column I Column II, (Ideal gas) (Related equations) (A) Reversible (P) w = nRTln P2 P1 isothermal process (B) Reversible (Q) w = nCV,m(T2 − T1 ) adiabatic process (C) Irreversible (R) PV = nRT process adiabatic (D) Irreversible (S) w = − ∫ V1 V2 Peat ⋅ dV isothermal process (1) A → P, R, S; B → Q, R, S; C → Q, R; D → R, S (2) A → R, Q; B → R, S; C → Q, R, S, ; D → P, Q, R, (3) A → R, Q; B → P, S; C → Q, R, S; D → P, Q, R (4) A → P, S; B → P, Q, R, S; C → R, S; D → P, Q, R 16. Match the columns (Given process does not include chemical reaction and phase change). Column I Column II Column I (Relation) Column II (Applicable to) (A) ΔH = ΔU + Δ(PV) (P) Any matter undergoing any process. (B) ΔH = n ⋅ CP,m ⋅ ΔT (Q) Isochoric process involving any substance. (C) q = ΔU (R) Ideal gas, under any process. (S) Ideal gas under isothermal process. (1) A → P, Q, R, S; B → R, S; C → Q (2) A → R, Q; B → R, S; C → R, P (3) A → R, S; B → P, R; C → Q (4) A → R, S; B → Q, P; C → S 17. Match the process of Column I with entropy or enthalpy change in Column II. Column I Column II (A) N2(g) + O2(g) (P) ΔS ≈ 0 → 2NO(g) (B) 2KI(aq) + (Q) ΔS < 0 HgI2(aq) → K2[HgI4](aq) (C) PCl5(g) → (R) ΔH > 0 PCl3(g) + Cl2(g) (D) NH3(g) + HCl(g) (S) ΔH < 0 → NH4Cl(s) (1) A → P, R; B → Q, S; C → R,; D → Q, S (2) A → R, Q; B → R, S; C → R, P; D → P, S (3) A → R, S; B → P, R; C → Q; D → S (4) A → R, S; B → Q, P; C → S, Q; D → P, Q
3 Answer Key 1 . ( 2 ) 2 . ( 4 ) 3 . ( 2 ) 4 . ( 1 ) 5 . ( 2 ) 6 . (1, 2, 3 ) 7 . ( 3 ) 8 . (1, 2, 3, 4 ) 9 . ( 2 ) 10 . ( 1 ) 11 . ( 3 ) 12 . ( 7 ) 13 . ( 3 ) 14 . ( 3 ) 15 . ( 1 ) 16 . ( 1 ) 17 . ( 1 )