Heating potassium chlorate results in chemical change.
Potassium chlorate is a white crystalline solid. Forms a very flammable mixture with combustible materials. Its mixture may be explosive if combustible material is very finely divided. Mixture may be ignited by friction. Contact with strong sulfuric acid may cause fires or explosions. May spontaneously decompose and ignite when mixed with ammonium salts. May explode under prolonged exposure to heat or fire. It is used to make matches, paper, explosives, and many other uses.
Heating potassium chlorate produces potassium chloride and oxygen gas.
When heat is given off in a chemical change or reaction, it is called an exothermic reaction. When heat is absorbed in a chemical change or reaction, it is called an endothermic reaction.
There are several differences between a physical and chemical change in matter or substances.
A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.
Physical changes can be reversed, chemical changes cannot be reversed with the substance changed back without extraordinary means, if at all.