A 1.00-mol sample of phosphorus pentachloride is placed in a 10.0-L reaction flask and allowedd to come to equilibrium at 250 C: PCL5--> PCl3 +Cl2 if the amount og chlorine in the equilibrium mixture is 0.470mol, calculate (a) the euilibrium concentration of each gas, (b) Kc, (c) the fraction of PCl5 dissociated.