Free NCERT Solutions For Class 11 Chemistry Chapter 6 :Thermodynamics Free PDF Download 

Question 1:
Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) Whose value depends on temperature only.

Question 2:
For the process to occur under adiabatic conditions, the correct condition is:
(i) ∆T = 0
(ii) ∆p = 0
(iii) q = 0
(iv) w = 0

Question 3: The enthalpies of all elements in their standard states are: (i) unity (ii) zero (iii) < 0 (iv) different for each element.

Question 4: ∆U θ of combustion of methane is – X kJ mol-1 . The value of ∆H θ is (i) = ∆U θ (ii) > ∆U θ (iii) < ∆U θ (iv) = 0.

Question 5:
The enthalpy of combustion of methane, graphite and dihydrogen at 298 K are, -890.3 kJ mol-1,-393.5 kJ mol-1, and -285.8 kJ mol-1respectively. Enthalpy of formation of CH4(g) will be
(i) -74.8 kJ mol-1
(ii) -52.27 kJ mol-1
(iii) +74.8 kJ mol-1
(iv) +52.26 kJ mol-1

Question 6:
A reaction, A + B->C + D + q is found to have a positive entropy change. The reaction will be
(i) possible at high temperature
(ii) possible only at low temperature
(iii) not possible at any temperature
(iv) possible at any temperature

Question 7:
In a process, 701 J of heat is absorbed by a system and 394 J of work is done by the system. What is the change in internal energy for the process?

Question 8:
The reaction of cyanamide, NH2CN(s) with dioxygen was carried out in a bomb
calorimeter and U was found to be -742.7 KJ mol-1 at 298 K. Calculate the enthalpy change for the reaction at 298 K.

Question 9:
Calculate the number of kJ of heat necessary to raise the temperature of 60 g of aluminium from 35oC to 55oC. Molar heat capacity of Al is 24 J mol-1 K-1.

Question 10:
Calculate the enthalpy change on freezing of 1.0 mol of water at 10.0oC to ice at – 10.0oC. ,∆fus H = 6.03 KJ mot-1 at 0oC. Cp [H2O(l) ] = 75.3 J mol-1 K-1;Cp [H2O(s) ] = 36.8 J mol-1 K-1.

Question 11:
Enthalpy of combustion of carbon to carbon dioxide is -393.5 kJ mol-1 Calculate the heat released upon formation of 35.2 g of CO2 from carbon and dioxygen gas.

Question 12:
Enthalpies of formation of CO(g), CO2(g), N2O(g)and N2O4(g) are -110 ,-393, 81 kJ and 9.7 kJ mol-1 respectively. Find the value of ∆rH for the reaction:

Question 13:
What is the standard enthalpy of formation of NH3 gas?

Question 14:
Calculate the standard enthalpy of formation of CH3OH(l) from the following data:

Question 15:
Calculate the enthalpy change for the process

Question 16:
For an isolated system, ∆U = 0, what will be ∆S?

Question 17:
For the reaction at 298 K,
2A + B → C
∆H = 400 kJ mol-1 and ∆S = 0.2 kJ K-1 mol-1
At what temperature will the reaction become spontaneous considering ∆H and ∆S
to be constant over the temperature range?

Solution17:

Question 18:
For the reaction,

Question 19: For the reaction 2A(g) + B(g) → 2D(g) 2A(g) + B(g) → 2D(g)
∆Uθ = -10.5 kJ and ∆Sθ= -44.1 JK-1. Calculate ∆Gθ for the reaction, and predict whether there action may occur spontaneously.

Question 20:
The equilibrium constant for a reaction is 10. What will be the value of ∆Gθ? R =8.314 JK-1 mol-1, T = 300 K.

Question 21:
Comment on the thermodynamic stability of NO(g), given

Question 22:
Calculate the entropy change in surroundings when 1.00 mol of H2O(l) is formed under standard conditions. ∆fHθ = -286 kJ mol-1.