At a certain temperature, 0.800 mol of SO3 is placed in a 2.00-L container.

Question

2so3<->2so2 +o2

At equilibrium, 0.140 mol of O2 is present. Calculate Kc.

Answer 1

0.800 mol/2.00L = 0.400M
........2SO3 <==> 2SO2 + O2
I.....0.400M........0.....0
C.......-2x........2x.....x
E.....0400-2x......2x.....x

x = O2 = 0.140mol/2.00L = 0.07M
Then 2x = 0.140M = (SO2)
and 0.400-0.140 = 0.26M = (SO3)

Substitute these into the Kc expression and solve for Kc.