[wannalearn]

as i know, changing concentrations doesn't affect equilibrium constants.
but what about this, CaCO3 (s) <--> CaO (s) + CO2 (g)
here i think that: Kc=[CO2] because the rest are solids
now if we changed the concentration of CO2 how the Kc is not affected? if we increased [CO2] the Kc should increase??
pls i need an answer

[Borek]

You are confusing Q (reaction quotient) with Kc (equilibrium constant). Q equals Kc at equilibrium but systems don't have to be at equilibrium, so Q is not guaranteed to equal Kc in every case.