A reaction vessel contains NH3, N2, and H2 at equilibrium at a certain temperature.

Hello, I am doing a few practice problems for an upcoming exam and would appreciate the help!

A reaction vessel contains NH3, N2, and H2 at equilibrium at a certain temperature. The equilibrium concentrations are [NH3]=0.25 M, [N2]=0.011 M, and [H2]=1.91 M. Calculate the equilibrium constant Kc for the synthesis of ammonia (NH3) if the reaction is represented as:

N2(g)+3H2(g)<---->2NH3(g)

1/2N2(g)+3/2H2(g)<---->NH3(g)