Calculating the Equilibrium Constant Practice Test

For the equilibrium reaction $\text{COCl}_2(g)\rightleftharpoons \text{CO}(g)+\text{Cl}_2(g)$, the system is at equilibrium with $\text{COCl}_2=0.50,\text{M}$, $\text{CO}=0.10,\text{M}$, and $\text{Cl}_2=0.20,\text{M}$. What is $K_c$?

In a sealed vessel, the reaction $\text{H}_2(g)+\text{I}_2(g)\rightleftharpoons 2\text{HI}(g)$ is at equilibrium. The equilibrium concentrations are $\text{H}_2=0.20,\text{M}$, $\text{I}_2=0.20,\text{M}$, and $\text{HI}=0.80,\text{M}$. What is $K_c$?