Question

The equilibrium constant, K_p, for the following reaction is 2.01 at 500 K:

PCl₃(g) + Cl₂(g) PCl₅(g)

Calculate the equilibrium partial pressures of all species when PCl₃ and Cl₂, each at an intitial partial pressure of 1.47 atm, are introduced into an evacuated vessel at 500 K.

Answer 1

Reaction is

PCl₃ + Cl₂ = PCl₅ .

Initial 1.47 1.47

Equilibrium 1.47 -y 1.47 -y y

K_p = P_pcl5 / P_pcl3 × P_cl2 .

Kp = y / ( 1.47 - y ) × ( 1.47 - y ) .

2.01 = y / ( 1.47 - y )² .

Then find y after solving above equation.

And find partial pressure y . And 1.47 - y .