Phosphorus trichloride gas and chlorine gas react to form phosphorus pentachloride gas: PCl3(g)+Cl2(g)⇌PCl5(g) A 7.5-L gas vessel is charged with a mixture of PCl3(g) and Cl2(g) which is allowed to equilibrate at 450 K. At equilibrium the partial pressures of the three gases are PPCl3=0.124 atm PCl2=0.157 at and PCl5=1.30 atm Calculate Kc for this reaction at 450 K.