Question

The reaction N_2(g) + 3H2(g) ⇌ 2NH_3(g) has K_C = 0.500 at 400*C. Write the reaction quotient (Q_C) expression including the “i” subscripts. Then, find the value for Q_C if [N₂] = 0.015 M, [H₂] = 0.12 M, and [NH₃] = 0.00054 M. Compare this value with K_C and determine which direction the reaction will go towards.

Answer 1

Kc is the equilibrium constant for a reaction. It depends on the concentration of reactants and products when the equlibrium is reached.

Qc is called reaction quotient. It the ratio of concentration of product to reactants raised to their powder at any stage during the reaction.

Given, [NH3]=0.00054M [N2] = 0.015M

[H2]=0.12M

Then Qc= [NH3]_i²/ [N2]_i[H2]_i³

Qc= (0.00054*0.00054)/(0.015*0.12*0.12*0.12)

Qc= 0.01125

Given Kc= 0.500

Since, Qc < Kc. The reaction shifts in the forward direction.