The equlibrium constant Kc for the reaction: has the value of 4.00 at 500K. If a mixture of 1.00 mol CO and 1.00 mol H2O is allowed to reach equilibrium at this temperature in a 1.00L flask, calculate the equilibrium concentrations of each species in the flask.

Answer 1

You should have shown the reaction. I assume it is
CO(g) + H2O(g) ==>H2(g) + CO2(g)
If not, just ignore what follows.

Set up an ICE chart and solve.
initial:
CO = 1.00 mol/L
H2O = 1.00 mol/L
CO2 = 0
H2 = 0

change:
CO = -x
H2O = -x
H2 = x
CO2 = x

equilibrium:
CO = 1-x
H2O = 1-x
CO2 = x
H2 = x

Post your work if you get stuck.

Answer 2

Kc=(x)(x)/(1-x)(1-x)

What is x in this equation and is is 4.0 Kc?