Question

At a certain temperature, 0.840 mol of SO3 is placed in a 1.50-L container. At eqibrium, 0.140 mol of O2 is present. Calculate Kc Number K=

Answer 1

Initial concentration of SO3 = mol of SO3 / volume

= 0.840 mol / 1.50 L

= 0.560 M

final concentration of O2 = mol of O2 / volume

= 0.140 mol / 1.50 L

= 0.0933 M

ICE Table:

[02] [SO2] [S02] 0.56 -2x 0.56-2x initial change equilibrium +1x +2x +1x +2x

Given at equilibrium,

[O2] = 0.0933

+1x = 0.0933

x = 0.0933

Equilibrium constant expression is

Kc = [SO2]^2[O2]/[SO2]^2

Kc = (+2x)^2(+1x)/(0.56-2x)^2

Kc = (+2*0.0933)^2(+1*0.0933)/(0.56-2*0.0933)^2

Kc = 0.0233

Answer: 0.0233