Equilibrium constant K$_p$ for the reaction $\mathrm{CaCO_3 \rightleftharpoons CaO + CO_2}$ is 0.82 atm at 727°C. If 1 mole of CaCO$_3$ is placed in a closed container of 20 L and heated to this temperature, what amount of CaCO$_3$ would dissociate at equilibrium?