Endergonic means absorbing energy in the form of work. Its etymology stems from the suffix -ergonic as derived from the Greek root ergon meaning to work, combined with the prefix end- as derived from the Greek root en meaning put into. By thermodynamic standards, work, a form of energy, is defined normally to move from the surroundings (the external region) to the system (the internal region). Thus, an endergonic process, as contrasted with an exergonic process, is one where the system absorbs energy from the surroundings. Subsequently, during an endergonic process energy is put into the system. If the transformation occurs at constant pressure and temperature: ∆G > 0. An endergonic reaction is a chemical reaction that absorbs energy in the form of work. In thermodynamics, thermodynamic work is the quantity of energy transferred from one system to another. ... In a thermodynamics problem, the surroundings, or environment, are anything not part of the system. ... System (from Latin systÄ“ma, in turn from Greek systÄ“ma) is a set of entities, real or abstract, comprising a whole where each component interacts with or is related to at least one other component and they all serve a common objective. ... Look up exergonic in Wiktionary, the free dictionary. ... An endergonic reaction is a chemical reaction in which the change in free energy is positive. ... Vapours of hydrogen chloride in a beaker and ammonia in a test tube meet to form a cloud of a new substance, ammonium chloride A chemical reaction is a process that results in the interconversion of chemical substances. ...

An endergonic reaction is essentially the opposite of an exergonic reaction. Since endergonic reactions require energy, they form molecular bonds, which decreases entropy. These bonds are energy carriers, therefore the formation of these bonds require some energy input that which is endergonic.

'Cold packs' which become cold after mixing two liquids, exploit this property. In fact, a common reaction which is clearly endergonic is the mixing of Ammonium Chloride and water. There is a net drop in temperature of the reaction as a result of the solvation of Ammonium ion Ammonium chloride or Sal Ammoniac (chemically ammonium chloride (NH4Cl); also salmiac, nushadir salt, zalmiak, sal armagnac, sal armoniac, salmiakki, salmiak and salt armoniack) is, in its pure form, a clear white water-soluble crystalline salt with a biting, slightly sour taste. ... Solvation is the attraction and association of molecules of a solvent with molecules or ions of a solute. ... Fumes from hydrochloric acid and ammonia forming a white cloud of ammonium chloride Ammonium is also an old name for the Siwa Oasis in western Egypt. ...

See also