Burning is a chemical process by which two atoms or molecules will combine with each other. In burning, the two atoms or molecules will combine and release energy. ... When the molecules combine and release energy, it is released in the form of heat and often light.
In the case of burning wood, stored potential energy (in the form of chemical energy) in the log is released due to heating by other excited atoms. This chemical reaction is called combustion and requires oxygen. Combustion changes the potential chemical energy into kinetic energy in the form of heat.
Energy is used to break bonds in reactants, and energy is released when new bonds form in products. ... The law of conservation of energy states that matter cannot be created or destroyed. Whether a chemical reaction absorbs or releases energy, there is no overall change in the amount of energy during the reaction.