“A chemical explosion is the result of a chemical reaction or change of state which occurs, often over an exceedingly short space of time, with the generation of a large amount of heat and sometimes a large quantity of gas.”
Reference: Akhavan, Jacqueline. (2011). Chemistry of Explosives (3rd Edition). Royal Society of Chemistry.
An explosion results from a rapid release of energy from a chemical reaction or change of state. The energy is dissipated in the form of a pressure wave, projectiles, thermal radiation and acoustic energy.
Crowl & Louvar …full reference