2. Thermodynamics
1- A gas expanded against a constant pressure of 1 atm from a volume of 5L to 10L. During the process
system absorbs 400J of heat from the surrounding. Calculate the change in the internal energy of the
system.
3. Thermodynamics
2-A 5 liter cylinder contained 10 moles of hydrogen gas at 27 0c. Due to leakage entire gas escaped
into the atmosphere. The atmospheric pressure is 1 atm. Calculate the work done by the gas
assuming hydrogen to be an ideal gas.
4. Thermodynamics
3-the enthalpy change (h) for the reaction
N2(g) + 3H2(g) – 2NH3(g)
-92.38 KJ at 298 K. what is U at 298 K ? (R=8.314 J K_1 MOL 1)
5. Thermodynamics
4-Calculate the difference between the heats of reactions at constant
pressure and constant volume for the reaction
2C¬¬¬¬¬¬6H6(l) + 15O2(g) --- 12CO2 (g) + 6H2O(l) at 250C in kj.
6. Thermodynamics
5-The heat of combustion of methane CH4(g) is measured in a bomb calorimeter at
298.2 K and is found to be -885.50 kj mol-1 . Find the value of enthalpy change H.
7. Thermodynamics
6- 0.16 g of methane was subjected to combustion at 270C in a bomb calorimeter . The temperature
of the calorimeter system (including water ) was found to rise by 0.50C. Calculate the heat of
combustion of methane (i) at the constant volume and (ii) at constant pressure . The thermal capacity
of the calorimeter system is 17.7 kj K-1(R=8.314 JK-1 MOL-1).
8. Thermodynamics
7- 10 moles of a gas are heated at constant volume from 200C to 300C. Calculate the change in the
internal energy of the gas . The molar heat capcity of the gas at constant pressure Cp=6.82 cal K -1 mol-1
and R=1.987 cal K-1 mol-1 .
9. Thermodynamics
8- A gas expands from 3 dm3 to 5 dm3 against a constant pressure of 3.0 atm . The work done during
expansion is used to heat 10 moles of water at temperature 290 K . Calculate the final temperature of
water . Specific heat of water =4.184 J
K-1 g-1.
10. Thermodynamics
9- For the reaction NH4CL(s) ----NH3(g)+HCL at 250C enthalpy change H=+177kj mol-1 and
entropy change S= +285 J mol-1 K-1 calculate the free energy change G at 25 0C and predict
whether the reaction is spontaneous or not .
11. Thermodynamics
10- At 00c ice and water are in equilibrium and H=6.0 KJ mol-1 for the
process
H2O(S)--------H2O(l)
What will be S and G for the conversion of ice to liquid water ?
12. Thermodynamics
11- For a reaction Kp=1.8 x 10-7 at 300 K. what is the value of G at this temperature ?
(R=8.314 JK-1 mol-1)
13. Thermodynamics
12- Calculate the standard free energy change for the following reaction
Zn(s) + Cu2+--------- Zn2+(aq) + Cu(s)
Given: f G0[Cu2+ (aq)]= 65.0 kj mol-1
f G0 [Zn2+ (aq)]= -147.2 kj mol-1
14. Thermodynamics
13- Calculate the equilibrium constant for the following reaction at 298 K:
2H2O(l)--------2H2(g) + O2(g)
Given: f G0 [ H2O (l) ] = -273.2 kj mol-1
R= 8.314 J mol-1 K-1 .
