Question

At high temperature, 2.00 mol of CH2O was placed in a 4.00 L container where it decomposed via the equilibrium CH2O(g)<=>CO(g)+H2(g) . At equilibrium, the concentration of CO was measured to be 0.0317 M. What is Kc for this reaction at this temperature?

Answer 1

M CH2O = 2.0/4.0 = 0.50M
........CH2O ==> H2 + CO
I.......0.50M......0....0
C..........-x......x....x
E.......0.50-x......0.0317M
Now fill in the table.
x must be 0.0317 and 0.50-x = 0.468

Substitute in Kc expression and solve for Kc.