## Chemistry (4th Edition)

a)$$K_c = \frac{1}{[CO_2]}$$
1. Write the expression including all compounds of the reaction: $$K_c = \frac{[CaCO_3]}{[CaO][CO_2]}$$ 2. But, since $CaO$ and $CaCO_3$ appear in the solid state, their concentrations are approximately constant, so they will not appear in the Kc expression: $$K_c = \frac{1}{[CO_2]}$$