Question

chemical equation of limestone decompose into quicklime and carbon dioxide on heating

Answer 1

CaCO3-—CaO+CO2
calcium carbonate when heated gets decomposed into calcium oxide and carbon dioxide.It is generally an endothermic reaction.

Answer 2

When heated strongly it will glow an orange/yellow colour and gradually break down from being chunks to a fine white powder. Unless you trap it, the CO2 made is lost to the air.