Title 6.THERMODYNAMICS-1.pdf ✅

UNIT 05 THERMODYNAMICS Exercise 1: NCERT Based Topic-wise MCQs 5.0 INTRODUCTION 1. Which of the following statements is not true regarding the laws of thermodynamics? (a) It deals with energy changes of macroscopic systems. NCERT\Page-160 / N-136 (b) It deals with energy changes of microscopic systems. (c) It does not depends on the rate at which these energy transformations are carried out. (d) It depends on initial and final states of a system undergoing the change. 5.1 THERMODYNAMICS TERMS 2. Which of the following is closed system? (a) Jet engine NCERT Page-161 / N-137 (b) Tea placed in a steel kettle (c) Pressure cooker (d) Rocket engine during propulsion 3. The state of a thermodynamic system is described by its measurable or macroscopic (bulk) properties. These are (a) Pressure and volume NCERT/Page N-138 (b) Pressure, volume, temperature and amount (c) Volume, temperature and amount (d) Pressure and temperature 4. Enthalpy change (ΔH) of a system depends upon its (a) Initial state NCERT Page-167 / N-143 (b) Final state (c) Both on initial and final state (d) None of these 5. Which of the following factors affect the internal energy of the system? NCERT/Page-162 / N-138 (a) Heat passes into or out of the system. (b) Work is done on or by the system. (c) Matter enters or leaves the system. (d) All of the above 6. Adiabatic expansions of an ideal gas is accompanied by (a) decrease in ΔE NCERT Page N-140 (b) increase in temperature (c) decrease in ΔS

(b) Pressure change (c) Volume change (d) Temperature change 11. When 1mol of a gas is heated at constant volume, temperature is raised from 298 to 308K. If heat supplied to the gas is 500J, then which statement is correct? NCERT Page N-140 (a) q = w = 500J, ΔU = 0 (b) q = ΔU = 500J, w = 0 (c) q = −w = 500J, ΔU = 0 (d) ΔU = 0, q = w = −500J 12. Which of the following statements/relationships is not correct in thermodynamic changes? (a) ΔU = 0 (isothermal reversible expansion of a gas) NCERT/ Page-166 / N-142 (b) w = −nRTln V2 V1 (isothermal reversible expansion of an ideal gas) (c) w = nRTln V2 V1 (isothermal reversible expansion of an ideal gas) (d) For a system of constant volume, heat involved directly changes to internal energy. 13. An ideal gas expands in volume from 1 × 10−3 to 1 × 10−2m3 at 300K against a constant pressure of 1 × 105Nm−2 . The work done is (a) 270kJ (b) −900kJ (c) −900J (d) 900kJ 14. The difference between ΔH and ΔU is usually significant for systems consisting ofNCERT/ Page-167 / N-143 (a) only solids (b) only liquids (c) both solids and liquids (d) only gases 15. Assume each reaction is carried out in an open container. For which reaction will ΔH = ΔE ? (a) C(s) + 2H2O(g) → 2H2(g) + CO2 (g) 15. NCERT Page-167 / N-143 (b) PCl5(g) → PCl3(g) + Cl2(g) (c) 2CO(g) + O2(g) → 2CO2 (g) (d) H2 (g) +Br2 (g) → 2HBr(g) 16. For the reaction CO(g) + 1 2 O2(g) → CO2(g) Which one of the statement is correct at constant T and ? (a) ΔH = ΔE NCERT Page-167 / N-143 (b) ΔH < ΔE (c) ΔH > ΔE (d) ΔH is independent of physical state of the reactants 17. For the reaction NCERT/ Page N-143 C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l) at constant temperature, ΔH − ΔE is (a) −RT (b) +RT