Limestone is mainly calcium carbonate, CaCO3, which when heated breaks down to form calcium oxide and carbon dioxide. Calcium oxide reacts with water to produce calcium hydroxide. Limestone and its products have many uses, including being used to make cement, mortar and concrete.

Thermal decomposition

Calcium carbonate breaks down when heated strongly. This reaction is calledthermal decomposition. Here are the equations for the thermal decomposition of calcium carbonate:

calcium carbonatecalcium oxide + carbon dioxide

CaCO3CaO + CO2

Other metal carbonates decompose in the same way, including:

• sodium carbonate
• magnesium carbonate
• copper carbonate

For example, here are the equations for the thermal…