A sealed 2.50 L container at 700 K contains an equilibrium mixture for the reaction 2 SO2(g) + O2(g) ⇌ 2 SO3(g). At equilibrium the container holds 0.350 mol SO2, 0.150 mol O2, and 0.400 mol SO3. Determine the equilibrium constant, Kc, for the reaction at 700 K.