Consider the following equilibrium. Suppose that 0.75 mol HI, 0.025 mol H, and 0.025 mol 12 are placed into a sealed 20.0 L flask and heated to 745 K. (a) Is the system at equilibrium? (b) If not, in which direction must the reaction proceed to reach equilibrium? Explain your answer. (c) Calculate the equilibrium concentrations of all three substances. The equilibrium constant for the reaction is Kc = 50.0 at 745 K. H(g) + 12(g) = HI(g)