Question

Phosphorus pentachloride dissociates on heating:
PCl5(g) ⇄ PCl3(g) + Cl2(g) 𝝙H = 1901 kJ/mol
(a) If Kc equals 3.26  102
at 191°C, what is Kp at this temperature?
(b) State the direction (toward product, toward reactant, no change) that the equilibrium
will shift when each of the following changes occurs. Briefly explain your answers.
PCl5 is added to the system
(i) Pressure is increased
(ii) Volume is increased
(iii) Temperature
(iv) Addition of a catalyst
(v) What change would you expect in the value of equilibrium constant by
increasing the temperature?

Answer 1

pressure squeezes it back left to the fewer mols of gas
volume lets it expand to the right
Temp (heat in) is what you used to make it happen in the first place

Answer 2

(a) Kp = Kc*(RT)^delta n. You have Kc and R and T. Be sure to convert T to kelvin.