[Ahmed Abdullah]

Does pressure has any effect over Kc of a reaction (gas phase, number of molecules changes)?
Let the following be a reaction composed of gaseous phases,
C<=>2D

Now, Kc= [D]^2/[C] [C], [D] =concentrationof C and D at equilibrium position.

When pressure is doubled Both the concentration of C and D is also doubled (assuming that the process is isothermal), that makes the value of Kc doubled (if no counterbalance occurs). But Kc is a constant so to maintain its fixed value the concentration of C should also increase.

That seems to explain why the equilibrium should shift toward left as pressure is applied.
Am I correct?


Now which factors effect Kc and Kp other than temperature?

[Padfoot]

That seems to explain why the equilibrium should shift toward left as pressure is applied.
Am I correct?

Correct.

Note that increasing pressure will not always push equilibruim to reactants side.  It only happens to in this case as there are less mol of gas on the reactant side.