Question

For the exothermic reaction
PCl3(g)+Cl2(g)⇌PCl5(g)

K = 0.160 at a certain temperature.
A flask is charged with 0.507 bar PCl3 , 0.507 bar Cl2, and 0.304 bar PCl5 at this temperature.

What are the equilibrium partial pressures of PCl3 , Cl2, and PCl5, respectively?

Answer 1

I assume that is Kp that is 0.160. First, you must determine which way the rxn moves; i.e., to the left or to the right. Do that with Qsp. Plug in the values and I get Qsp = about 1.2 which means the rxn will reach equilibrium by moving to the left.

...........PCl3 + Cl2 ⇌ PCl5
I.........0.507..0.0.507...0.304
C.........+p.........+p.....-p
E......0.0507+p...0.0507+p..-0.304=p

Plug the E line into the Kp expressdion and solve for p, then evaluate the E line for individual values.