The symbol equation for heating limestone (calcium carbonate) is:

CaCO₃(s) → CaO(s) + CO₂(g)

Where:

* CaCO₃ represents calcium carbonate (limestone)

* CaO represents calcium oxide (quicklime)

* CO₂ represents carbon dioxide gas

* (s) indicates a solid state

* (g) indicates a gaseous state

This equation shows that when limestone is heated, it decomposes into calcium oxide and carbon dioxide.