A mixture initially contains A, B, and C in the following concentrations: [A] = 0.600 M, [B] = 1.00 M, and [C] = 0.400 M. The following reaction occurs and equilibrium is established:
A 2B <-> C
At equilibrium, [A] = 0.420 M and [C] = 0.580 M. Calculate the value of the equilibrium constant, Kc.