What is a chemical reaction that releases energy by light or heat?

A chemical reaction that releases energy in the form of light or heat is known as an exothermic reaction. During this process, the total energy of the products is lower than that of the reactants, resulting in the release of energy to the surroundings. Common examples include combustion reactions, such as burning wood or fossil fuels, where energy is emitted as heat and light. Another example is the reaction of certain metals with acids, which can also produce heat and sometimes light.