burning...............

Burning is a chemical change because it involves changes in the chemical composition of the reactants.

In simple terms the molecular formulae of all the reactants and products are different.

For example, when fuel is burnt in the presence of oxygen, carbon dioxide and water are formed. This is accompanied by the release of large amount of energy.

So, here fuel is a hydrocarbon , oxygen is O₂, carbon dioxide is CO₂ and water is H₂O. All have completely different molecular formula. So, it is a chemical change.