#### Thermodynamics Two Marks Questions

11th Standard

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Chemistry

Time : 00:45:00 Hrs
Total Marks : 30
15 x 2 = 30
1. Define molar heat capacity. Give its unit

2. Define the calorific value of food. What is the unit of calorific value?

3. Define enthalpy of neutralization

4. What is lattice energy?

5. Give Kelvin statement of second law of thermodynamics.

6. Define molar heat capacity at constant volume and molar heat capacity at constant pressure.

7. Explain why Cp is always greater than Cv?

8. Describe the application of heat of combustion.

9. The bond dissociation energies of gaseous chlorine, hydrogen, and hydrogen chloride are 104, 58, and 103 k.cal mol-1 respectively. Calculate the enthalpy of formation of HCI(g). Predict in which of the following, entropy increases/decreases. - Temperature of crystalline solid is raised from 0K to 115K.

10. The bond dissociation energies of gaseous chlorine, hydrogen, and hydrogen chloride are 104, 58, and 103 k.cal mol-1 respectively. Calculate the enthalpy of formation of HCI(g). Predict in which of the following, entropy increases/decreases. - 2NaHCO3(s) $\rightarrow$Na2CO3(s) + CO2(g) + H2O(s)

11. For the reaction, 2A(g) + B(g) ⟶  2D(g) ΔU= -10.5 kJ and ΔS0 = - 44.1 JK-1. Calculate ΔG for the reaction and predict whether the reaction is spontaneous or not.

12. For the equilibrium PCI5(s) ⇌ PCl3(g) + CI2(g) at 25°C kc = 1.8 x 10-7 R = 8.314 Jk-1 mol-Calculate ΔGo for the reaction.

13. An engine operating between 127°C and 47°C takes some specified amount of heat from a high temperature reservoir. Assuming that there are no frictional losses, calculate the percentage efficiency of an engine.

14. The equilibrium constant for the reaction is 10. Calculate the value of $\Delta { G }^{ \ominus }$;  Given R = 8.314 JK-1 mol-1; T = 300 K.

15. Calculate the entropy change in surroundings when 1 mol of H20(I) is formed under standard conditions. Given $\Delta { H }^{ \ominus }$ = - 286 kJ mol-1.