#### Thermodynamics Model Question Paper

11th Standard

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5

(a)

q = 0

(b)

dP = 0

(c)

dT = 0

(d)

dP = 0

2. Which among the following is an intensive property?

(a)

free energy

(b)

heat capacity

(c)

volume

(d)

molar volume

3. For an isochoric process, ΔU=-----

(a)

w

(b)

q+w

(c)

qv

(d)

0

4. If the heat flows out of the system into the surrounding, the q value becomes -------

(a)

+Ve

(b)

-Ve

(c)

equal to zero

(d)

maximum

5. The extensive and intensive properties respectively are

(a)

entropy, enthalpy

(b)

entropy, temperature

(c)

enthalpy, entropy

(d)

temperature, entropy

6. 5 x 2 = 10
7. Give expressions for the entropy change a-phase change.

8. Two litres of an ideal gas at a pressure of 10 atm expands isothermally into vacuum until its total volume is 10 litres. How much heat is absorbed and how much work is done in the expansion.

9. 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.

10. 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.

11. Define Zeroth law of thermodynamics (or) Law of thermal equilibrium.

12. 5 x 3 = 15
13. Predict the change in internal energy for an isolated system at constant volume.

14. One mole of a gaseous system absorbs 100 J of heat and does work equivalent to 50 J. Calculate the change in the internal energy of the system.

15. Bring out the differences between extensive and intensive properties.

16. Define standard enthalpy changes.

17. Drive the relation between cp and cv for an ideal gas.

18. 4 x 5 = 20
19. Calculate the standard entropy of formation $\Delta { S }_{ f }^{ o }$ of CO2(g). Given the standard entropies of CO2(g), C(s), O2(g) as 218.8, 8.740 and 205.60 Jk-1 respectively.

20. Calculate the entropy change of a process possessing ΔHt = 2090 J mole-1.

21. Show that the reaction  $CO+\frac { 1 }{ 2 } { O }_{ 2 }\longrightarrow { CO }_{ 2 }$   at 300K is spontaneous. The standard Gibbs free energies of formation of CO2 and CO are -394.4 and -137.2 KJ mole-1 respectively.

22. 1 mole of an ideal gas is maintained at 4.1 atm and at a certain temperature absorbs 3710J heat and expands to 2 Iitres. Calculate the entropy change in expansion process.