Endothermicity

Endothermicity refers to a process that absorbs heat from its surroundings. In chemistry, this is often described as an endothermic reaction. These reactions require energy input to proceed, typically in the form of heat. As heat is absorbed, the temperature of the surroundings decreases, making the reaction feel cold to the touch. Common examples include the melting of ice, the evaporation of water, and the chemical reaction in instant cold packs.

The change in enthalpy, denoted as ΔH, for an endothermic process is positive. This indicates that the system has gained energy from its environment. The bonds within the reactants in an endothermic reaction are stronger, or more stable, than the bonds formed in the products. Therefore, energy must be supplied to break these stronger bonds, and the energy released when forming the new bonds in the products is less than the energy required to break the original bonds.

Endothermic processes are contrasted with exothermic processes, which release heat into their surroundings, causing a temperature increase. In biological systems, endothermy refers to the ability of an organism to generate heat internally, maintaining a stable body temperature regardless of external conditions. This is often associated with warm-blooded animals like mammals and birds.