Consider the reaction: 2NO(g) + 2H_2(g) rlharN_2 (g) 2H_2O(g) At a certain temperature, the equilibrium concentrations [NO] = 0.31 M, [H_2] = 0.16 M, [N_2] = 0.082 M, and [H_2O] = 4.64 M. Write the equilibrium expression for the reaction. Determine the value of the equilibrium constant.