Reaction in which a substance get oxidized,means that it gains O2 and loses H2.Exothermic reaction are those in which heat is evolved.And endothermic reaction are those in which heat is absorbed.
in a chemical reaction if oxygen are added that type of reaction is known as oxidation reaction or the removal of hydrogen from a substance is also called oxidation reaction .eg:- 2Cu+O2 gives 2CuO
Do not clear understand oxidation
An exothermic process releases heat, causing the temperature of the immediate surroundings to rise. An endothermic process absorbs heat and cools the surroundings.”
In an oxidation-reduction, or redox, reaction, one atom or compound will steal electrons from another atom or compound. A classic example of a redox reaction is rusting. When rusting happens, oxygen steals electrons from iron. Oxygen gets reduced while iron gets oxidized.