1. The problem statement, all variables and given/known data When 1.000 mol PCl5 is intorduced into a 5.000L container @500K, 78.50% of PCl5 dissociates to give equilibrium mixture PCl5, PCl3, Cl2 : PCl5--->PCl3+Cl2 (this eq. is reversible) (a) calculate Kc and Kp (b) if the initial concentrations are [PCl5]=.500M, [PCl3]=.150M, and [Cl2=.600], in which direction does the rx proceed to reach equilibrium? what are the concentrations when the mixture reaches equilibrium? 2. Relevant equations Kc=[Products]/[reactants] Kp=Kc(RT)^n 3. The attempt at a solution I attempted to find Kc of the initial problem, by getting the molarity (.2) of the reactant. I then multiplied by .785 to get the percent to put in the numerator, but am not getting the right answer in the book. I know in part b i must use the chart to convert to quadratic equation, but am having trouble with the first part (surprisingly, as its usually the second part which gives me trouble). I have tried this either which way and still can not get the right answer. Any input would be great. Thanks!