Textbook Problem 5I.27 part c

[Trisha Mantri 3L]

I understand how to answer parts a and b of this question, but I'm not sure where to start for part c. It asks "what is the equilibrium composition of the reaction system," but I'm not sure how/where to start solving this problem. Could anyone explain to me how they solved this?

[Anthony Tam]

You basically set up an ICE table with the concentrations you calculated in part a. In part b, you also saw that Q is less than K so the reaction will proceed right. As a result, the change in the ICE table should be -x for the reactants and +x for the product. Then you use K and the quadratic formula to solve for x. After solving for x, you plug it back into the E in the last row of the ICE table and solve for the concentrations of each reactant and product.

[Mia Hansen 2I]

for part c you set up the ice table. this is the one I got:
PCl3+Cl2 <->PCl5
I 6 1 3
C -x -x +x
E 6-x. 1-x 3+x
then you solve for x using the Kc value so you can solve for each of the equilibrium concentrations