Kf and Kp

[zmike]

Why is that the Kf (thermodynamic equilibrium constant) exact and not dependent on temperature meanwhile Kp (apparent equilibrium constant) is dependent on temperature.
They are essentially the same formula except for an activity coefficient which doesn't change in response to temperature??

also does Kf (thermodynamic equilibrium constant) is independent or dependent of pressure because

I know Kp (apparent equilibrium constant) is dependent on pressure. Does Kf depend on the partial pressure of the gases in a mixture? if so, is it the activity coefficient that compensates for this change (a different coefficient for each mixture of pressures)?

thank you

[janhaa]

well, the equilibrium constant is dependent on temperature according to van't Hoff equation

\ln(\frac{K_2}{K_1})=\frac{\Delta H}{R}\left({1\over T_1}-{1\over T_2}\right)

where \Delta H is the enthalpy of reaction
---------------------------