Question

Why is combustion considered to be a chemical change ?​

Answer 1

Combustion reactions always involve molecular oxygen O2. Anytime anything burns (in the usual sense), it is a combustion reaction. Combustion reactions are almost always exothermic (i.e., they give off heat). ... When organic molecules combust the reaction products are carbon dioxide and water (as well as heat).

Answer 2

because it is start from chemical and when it is change they use oxygen and carbon dioxide.