Endothermic and Exothermic Reactions

Endothermic and Exothermic Reactions


Every single chemical reaction involves some kind of change in energy which fall into one of two categories Endothermic or Exothermic.

An endothermic reaction is one that absorbs energy. For example: instant ice packs absorb energy and are therefore endothermic.

An exothermic reaction is one that releases energy.  For example explosions release energy and are therefore exothermic.

At an atomic level... molecules are held together by chemical bonds.  These bonds can break if energy is added and they can form together if energy is given off to form bonds.

In an endothermic reaction it takes more energy to break the bonds then the reaction gives off.  But in an exothermic reaction it takes less energy to break the bonds then the reaction gives off to form bonds.

For an in-classroom demonstration of types of endothermic and exothermic reactions watch this video!