Metal carbonates such as calcium carbonate break down when heated strongly. This is called thermal decomposition. Here are the equations for the thermal decomposition of calcium carbonate:
calcium carbonate calcium oxide + carbon dioxide
CaCO3 CaO + CO2
Other metal carbonates decompose in the same way. Here are the equations for the thermal decomposition of copper carbonate:
copper carbonate copper oxide + carbon dioxide
CuCO3 CuO + CO2
Calcium carbonate also reacts with acid to make a calcium salt, carbon dioxide and water.
calcium carbonate + sulphuric acid → calcium sulphate + carbon dioxide + water
CaCO3 + H2SO4 → CaSO4 + CO2 + H2O
The type of salt produced depends on the type of acid. For example a reaction with hydrochloric acid would make a chloride (e.g. CaCl2)
Other carbonates that react with acids are magnesium, copper, zinc and sodium.