Equilibrium Constant of a Heterogeneous Reaction

[Saracen Rue]

Homework Statement

Write an expression for K_c for the following at equilibrium;
CaCO_3(s) + CO_2(g) + H₂O_(l) ⇔ Ca²⁺_(aq) + 2HCO₃^-_(aq)

Homework Equations

K = [products]^(coefficients)/[products]^(coefficients)

The Attempt at a Solution

I know that pure solid and liquid substances should be set to 1 when calculating the equilibrium constant. However, I haven't encounter an equation before where both aqueous and gaseous substances are present. Does this effect how I should set up the equation for the equilibrium constant at all? Thank you for your time

 

[Borek]

You should use a partial pressure of the gas.