A student ran the following reaction in the laboratory at 481 K: PCl3(g) + Cl2(g) PCl5(g) When she introduced PCl3(g) and Cl2(g) into a 1.00 L evacuated container, so that the initial partial pressure of PCl3 was 2.31 atm and the initial partial pressure of Cl2 was 1.71 atm, she found that the equilibrium partial pressure of Cl2 was 0.325 atm. Calculate the equilibrium constant, Kp, she obtained for this reaction.