Phosphorus pentachloride gives an equilibrium mixture of PCl5, PCl3, and Cl2 when heated
PCl5(g) PCl3(g) + Cl2(g)
A 1.00 L vessel contains an unknown amount of PCl5 and 0.020 mol each of PCl3 and Cl2 at equilibrium at 250?C. How many moles of PCl5 are in the vessel if Kc for this reaction is 0.0415 at 250?C.