General Chemistry II
posted by Rosi .
The equillibrium constant (Kp) for the interconversion of PCl5 and PCl3 is 0.0121:
PCl5(g) > PCl3(g) + Cl2(g)
A vessel is charged with PCl5, giving a initial pressure of 0.123 atm. At equillibrium, the partial pressure of PCl3 is _____ atm.

.........PCl5 ==> PCl3 + Cl2
initial...0.123.....0.......0
change...2p........p.......p
equil...0.1232p.....p......p
Substitute the equilibrium values into the expression for Kp and solve for p.
Post your work if you get stuck. 
.0330