Exercise 1.              

      Calculate the equilibrium pressure of each reactant of given reaction with the help of following data.

      A + B  C + D

      Initial pressure of A and B are 6 atm and 5 atm. The equilibrium pressure of C and D are 2 atm in each case.

Exercise 2 .                         

      The equilibrium constant for the reaction

      PCl_5(g)  PCl_3(g) + Cl_2(g) is 2.4 × 10^–3. Determine the equilibrium constant for the reverse reaction at same temperature.

Exercise 3                           

      At 21.5°C and a total pressure of 0.0787 atm, N₂O₄ is 48.3% dissociated into NO₂. Calculate K_p and K_c for the reaction.

      N₂O_4(g)  2NO_2(g)

Exercise 4 .

(i) Write the expression for K_p and K_c for the following reactions.

N₂ + 3H₂  2NH₃

(ii) Find out the heterogeneous equilibrium from the following reaction

      (A) CaCO₃ (s)  CaO(s) + CO₂ (g)

      (B) H₂(g) + I₂(g)      2HI (g)

Exercis 5      

      What is the value of equilibrium constant for the following reaction

       If  A   D

       A  B     K₁ = 2

       B   C    K₂ = 5

       C  D     K₃ = 3  

Exercise 6.

      In an equilibrium A + B —> C + D; A and B are mixed in a vessel at temperature T. The initial concentration of A was twice the initial concentration of B. After the equilibrium has established, concentration of C was thrice the equilibrium concentration of B. Calculate K_c.

Exercise .7

      Ammonium hydrogen sulphide dissociates as follows

      NH₄HS(s)  NH₃(g) + H₂S(g)

      If solid NH₄HS is placed in an evacuated flask at certain temperature it will dissociate until the total pressure is 600 torr.

       (a) Calculate the value of equilibrium constant for the dissociation reaction

       (b) Additional NH₃ is introduced into the equilibrium mixture without changing the temperature until partial pressure of NH₃ is 750 torr, what is the partial pressure of H₂S under these conditions? What is the total pressure in the flask?

Exercise .8

      At 700 K hydrogen and bromine react to form hydrogen bromide. The value of equilibrium constant for this reaction is 5 × 10⁸. Calculate the amount of H₂, Br₂ and HBr at equilibrium if a mixture of 0.6 mole of H₂ and 0.2 mole of Br₂ is heated to 700 K.

Exercise 9

      The equilibrium constant is 0.403 at 1000K for the process

                  FeO_(s) + CO_(g)  Fe_(s)+ CO_2)g)

      A steam of pure CO is passed over powdered FeO at 1000K until equilibrium is reached. What is the mole fraction of CO in the gas stream leaving the reaction zone?

Exercise 10 .           

      N₂ + 3H₂  2NH₃;           Δ H = negative

What are the conditions of temperature and pressure favorable for this reaction?

Exercise 11: Equilibrium constant K_p for the reaction 3/2 H_2(g) + 1/2 N_2(g)  NH_3(g) are 0.0266 and 0.0129 at 310°C and 400°C respectively. Calculate the heat of formation of gaseous ammonia. Standard Free Energy Change of a Reaction and its Equilibrium Constant

Exercise 12.

      What is the value of R if value of ΔG^O is in?

(i) Joules                         (ii) Calories

Exercise 13.

      N₂O₄ is 25% dissociated at 27°C and 1 atm pressure.

Calculate (i) Kp and (ii) the percentage dissociation at 0.1 atm and 27°C.       

ANSWERS TO EXERCISES

Exercise 1:

                        A ——> 4 atm

                        B ——> 3 atm

Exercise 2:

                        4.16 × 10²

Exercise 3:

                        K_p = 0.0956 atm

                        K_c = 3.96 × 10^–3 mole/lit

Exercise 4:   (i)   K_c = [NH₃]² / [N₂] [H₂]³

                              K_p = 

                        (ii) (A) is a heterogeneous equilibrium.

Exercise 5:  

                        K = 30

Exercise 6:        

                        1.8

Exercise 7:  

            (a)       0.155 atm²

            (b)       119.32 torr, 869.32 torr

Exercise 8:        

                        0.4, 0, 0.4

Exercise 9:

                        0.713

Exercise 10:

                        Low temperature, high pressure and high concentration of N₂ and H₂.

Exercise 11.

                     –12140 cals

Exercise 12:

            (i)         8.314 J mole^-1K^-1

            (ii)        2 cal mole^-1K^-1

Exercise 13:      

            (i)         0.266 atm

            (ii)        93.27%