A chemical reaction involves the breaking up of chemical bonds between atoms resulting in the absorption of energy and simultaneously the formation of bonds with the release of energy.
A chemical reaction is in which the bonds are broken within reactant molecules, and new bonds are formed within product molecules in order to form a new substance. It is usually accompanied by a release of energy when a chemical bond is broken. Likewise, an input of energy is needed for the formation of chemical bonds. The supplied/released energy can come in different ways, such as heat, light, and electricity.
In general, endothermic reactions include the formation of chemical bonds by heat absorption from the surroundings.
- The melting of ice to form water.
- The baking of bread
The release of heat energy produced from bond-breakage involves exothermic reactions.
Generally referred to as burning, combustion is an exothermic reaction wherein, when exposed to an oxidizing agent, a fuel undergoes reduction and becomes an oxidized substance.