Definition of Endothermic Reaction
Endothermic reactions or processes are such reactions in which the energy is absorbed. The energy is absorbed in the form of heat. These reactions utilize external energy to carry out the process. When the heat is drawn in during the reaction, this tends to cool down the surroundings as a result.
As the energy is absorbed, so the total energy of the products is more than that of the total energy of the reactants. Hence, the enthalpy change is always positive for such reactions. An example of an endothermic reaction is the reaction of the melting of an ice cube as heat is required to change its state from solid to liquid.