Question

1. Consider 1.20 mol of carbon monoxide and 4.00 mol of chlorine sealed in a 6.00 L container at 476 oC. The equilibrium constant, Kc, is 2.50 (in M-1) for

CO(g) + Cl2(g) ? COCl2(g)

Calculate the equilibrium molar concentration of CO.

2. For the reaction in the previous problem, that is,

2HI(g) ? H2(g) + I2(g) Keq = 0.016

Initially a container contains 0.40 M HI and no product. What is the equilibrium concentration of H2?

Answer 1

Ans 1

Initial concentration of CO = moles/Volume

= 1.20 mol / 6L

= 0.2 M

Initial concentration of Cl = moles/Volume

= 4 mol / 6L

= 0.66 M

Balanced equation with ICE table

CO(g) + Cl2(g) ? COCl2(g)

I 0.2 0.66

C - x - x +x

E (0.2-x) (0.66-x) x

Equilibrium constant expression of the reaction

Kc = [COCl2] /[CO] [Cl2]

2.50 = x / (0.2-x)(0.66-x)

2.50(0.2-x)(0.66-x) - x = 0

(0.5-x)(0.66-x)-x = 0

0.33 - 0.66x - 0.5x - x + x^2 = 0

0.33 - 2.16x + x^2 = 0

x = 0.165

equilibrium molar concentration of CO

= 0.2 - x

= 0.2 - 0.165

= 0.035 M