Anything which changes the composition of starting material is a chemical property or chemical change. For example: you bake cake or cook food the heat changes composition of these. So cooking is a chemical change.
But evaporation of water is a physical change because even after evaporating it is still water molecules not changed to something else.
Combustion of any substance is burning of any substance in air. Combustion is actually the burning of a substance with oxygen in air. So, when a substance undergoes combustion it changes in it’s composition.
COMBUSTION IS A CHEMICAL CHANGE
