What is the difference between an endothermic and exothermic reaction?

(Using a diagram of energy changes) The simplest way of thinking about it is that exothermic reactions release energy, such as heat, to the surroundings whereas endothermic reactions absorb energy from the surroundings. This is because in an exothermic reaction the bonds in the products are stronger and more stable than in the reactants, while the opposite will be true for an endothermic reaction. Another way of thinking about it is that exothermic reactions are making bonds and endothermic reactions are breaking bonds. You can remember this by thinking MEXOBENDO --> MEXO= making bonds is exothermic BENDO = breaking bonds is endothermic. An example of an exothermic reaction is combustion, and one of an endothermic reaction is melting ice.