Endothermic

In thermodynamics, the word endothermic "within-heating" describes a process or reaction that absorbs energy in the form of heat. Its etymology stems from the Greek prefix "endo-," meaning “inside” and the Greek suffix "–thermic", meaning “to heat”. The opposite of an endothermic process is an exothermic process, one that releases energy in the form of heat. The term “endothermic” was coined by Marcellin Berthelot.

The concept is frequently applied in physical sciences to e.g. chemical reactions, where thermal energy (heat) is converted to chemical bond energy.

Overview

Endothermic, also incorrectly known as endergonic, refers to a transformation in which a system receives heat from the surroundings:: "Q > 0

When the transformation occurs at constant pressure:

:"∆H > 0"

and constant volume:

:"∆U > 0"

If the surroundings do not supply heat (e.g., when the system is adiabatic), an endothermic transformation leads to a decrease in the temperature of the system. [cite book | last = Perrot | first = Pierre | title = A to Z of Thermodynamics | publisher = Oxford University Press | year = 1998 | id = ISBN 0-19-856552-6 ]

Endothermic processes

Some examples of endothermic processes are: [ [http://antoine.frostburg.edu/chem/senese/101/thermo/faq/exothermic-endothermic-examples.shtml Exothermic - Endothermic examples] ]
* Melting of ice
* Depressurising a pressure can

Implications for chemical reactions

Chemical endothermic reactions need heat to be performed. In a thermochemical reaction that is endothermic, the heat is placed on the reactants side (heat is necessary for and absorbed during the reaction).

Applications of endothermic processes

Endothermic materials in passive fire protection

Endothermic substances, both natural, e.g. gypsum, and synthetic, e.g. resin-based intumescents, are popular for use in heat shielding, ablation, materials in space physics, fireproofing, e.g. fire-resistive coatings for LPG vessels, and compartmentalisation of fire in buildings, which is the cornerstone of passive fire protection. Typically, the technological basis is the conversion of hydrates, or chemically-bound water into vapour, or steam.

ee also

* Endergonic
** Endergonic reaction
* Exergonic
** Exergonic reaction

References

External links

* [http://www.ilpi.com/msds/ref/exothermic.html Endothermic Definition] - MSDS Hyper-Glossary
* [http://tobias.kieser.googlepages.com/endothermicreaction School experiment]


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Look at other dictionaries:

  • Endothermic — En do*ther mic, a. [Pref. endo + thermic.] (Chem.) Designating, or pert. to, a reaction which occurs with absorption of heat; formed by such a reaction; as, an endothermic substance; opposed to {exothermic}. [Webster 1913 Suppl.] …   The Collaborative International Dictionary of English

  • endothermic — 1884, from Fr. endothermique (1879); see ENDO (Cf. endo ) + THERMAL (Cf. thermal) …   Etymology dictionary

  • endothermic — ► ADJECTIVE 1) Chemistry (of a reaction) accompanied by the absorption of heat. The opposite of EXOTHERMIC(Cf. ↑exothermic). 2) Zoology (of an animal) dependent on the internal generation of heat …   English terms dictionary

  • endothermic — [en΄dō thʉr′mik] adj. [ ENDO + THERMIC] designating, of, or produced by a chemical change in which there is an absorption of heat …   English World dictionary

  • endothermic — endoergic endoergic adj. occurring with absorption of energy. [Narrower terms: {endothermic}] {exoergic} Syn: energy absorbing. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • endothermic — Reactions that proceed with absorption of enthalpy (heat energy) are termed endothermic. See: exothermic …   Petroleum refining glossary

  • endothermic — UK [ˌendəʊˈθɜː(r)mɪk] / US [ˌendoʊˈθɜrmɪk] adjective chemistry an endothermic reaction is a chemical reaction in which heat is absorbed, not produced See: exothermic …   English dictionary

  • endothermic — adjective Etymology: International Scientific Vocabulary Date: 1884 1. characterized by or formed with absorption of heat 2. warm blooded …   New Collegiate Dictionary

  • endothermic — Process or reaction that absorbs heat and thus requires a source of external energy in order to proceed …   Dictionary of molecular biology

  • endothermic — endothermically, adv. endothermy, endothermism, n. /en doh therr mik/, adj. 1. Chem. noting or pertaining to a chemical change that is accompanied by an absorption of heat (opposed to exothermic). 2. Zool. warm blooded. Also, endothermal /en doh… …   Universalium

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