Phosphorus pentachloride decomposes according to the chemical equation:

PCl5(g)<--> PCl3(g)+Cl2(g)

Kc = 1.80 at 250 degrees Celsius

A 0.352 mol sample of PCl5(g) is injected into an empty 4.45 L reaction vessel held at 250 °C. Calculate the concentrations of PCl5(g) and PCl3(g) at equilibrium.

PCl5 = ?
PCl3 = ?

3 answers

do the ice table
species initial final
PCl5 .352/4.45 (.352/4.45-x)
PCl3 0 x
CL2 0 x
where numbers are in moles per liter

K=x^2/(.352/4.45-x)

you know k, solve for x, then the concentrations listed on your ICE table.
Thank you! What did you get as answers? My answers were not correct.
If you will post your work someone will be glad to find the error for you.