Question

2.00 moles of CO2 and 1.50 moles of H2 are placed into a rigid 5.00-L container and they react according to the equation ? ? CO2(g) + H2(g) ? CO(g) + H2O(g) ? ? K = 2.50 What will be the concentration of carbon monoxide when equilibrium is reached?

Answer 1

2.00 moles of CO2 and 1.50 moles of H2 are placed into a rigid 5.00-L container and they react according to the equation ? ? CO2(g) + H2(g) ? CO(g) + H2O(g) ? ? K = 2.50 What will be the concentration of carbon monoxide when equilibrium is reached?

Initial concentration of CO2 = moles / volume = 2 / 5 = 0.4 M

Initial concentraiton of H2 = moles / volume = 1.5 /5 = 0.3 M

The equation is

                          CO2(g) +       H2(g) ===> CO(g) + H2O(g)

Initial            0.4 0.3 0 0

Change -x -x +x    +x

Equilibrium    0.4-x 0.3-x    x x

Kc = 2.50 = [CO] [ H2O] / [CO2][H2] = x² / (0.4-x)(0.3-x)     = 2.50

x² = 2.50 [(0.4-x)(0.3-x)]

x² = 2.50x² + 0.3 - 0.6x

1.50 x² + 0.3 - 1.75x = 0

On solving

x = 0.209

[CO] = x = 0.209