Question

At 700 K, CCl4 decomposes to carbon and chlorine. The Kp for the decomposition is 0.76. Find the starting pressure of CCl4 at this temperature that will produce a atotal pressure of 1.9atm at equilibrium.

Answer 1

Reaction of CCl4 decomposition is following:
CCl4 (g) --> C (s) + 2Cl2 (g)
Kp = 0.76 = (P Cl2)^2/(P CCl4) carbon (C (s) is not included since it is in solid state and does not change volume
Ptotal = 1.9atm = P Cl2
P CCl4 * 0.76 = (P Cl2)^2
P CCl4 = 4.75atm