Heterogeneous Chemical Equilibrium with Calcium Carbonate
Solid calcium carbonate (CaCO3) decomposes into solid calcium oxide (CaO) and gaseous carbon dioxide (CO2) in a constant-volume container at high temperatures. CO2 is assumed to be an ideal gas, and the two solids are assumed to be in separate phases. You can vary the initial number of moles of CaCO3, CaO, and CO2 in the constant-volume container using sliders; the container displays the equilibrium pressure as the color intensity of the gas phase increases as the number of moles of CO2 increases. The bar graph on the right shows the number of moles present at equilibrium. The equilibrium constant Keq changes as the temperature changes using the slider. The equilibrium constant is equal to the CO2 pressure (in bar) divided by the standard-state pressure of 1 bar. Note that adding more CaO when CaO is already in the container (or adding more CaCO3 when CaCO3 is already in the container) at equilibrium does not change equilibrium because increasing the number of moles of a pure solid does not change its fugacity.

Download the CDF file to view the simulation using the free Wolfram CDF player.