AskDefine | Define endothermic

Dictionary Definition

endothermic adj : (of a chemical reaction or compound) occurring or formed with absorption of heat [syn: endothermal, heat-absorbing] [ant: exothermic]

User Contributed Dictionary

English

Etymology

From endo- "inside" + thermic "of heat"

Adjective

endothermic
  1. : Of a chemical reaction that absorbs heat energy from its surroundings.
  2. : Of an animal whose body temperature is regulated by internal factors.

Antonyms

Extensive Definition

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.

Endothermic processes

Some examples of endothermic processes are:
  • 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.

References

External links

endothermic in Arabic: تفاعل ماص للحرارة
endothermic in Catalan: Reacció endotèrmica
endothermic in Danish: Endoterm
endothermic in German: Endotherme Reaktion
endothermic in Estonian: Endotermiline reaktsioon
endothermic in Spanish: Reacción endotérmica
endothermic in French: Réaction endothermique
endothermic in Galician: Reacción endotérmica
endothermic in Italian: Processo endotermico
endothermic in Hebrew: תגובה אנדותרמית
endothermic in Lithuanian: Endoterminis procesas
endothermic in Hungarian: Endoterm reakció
endothermic in Dutch: Endotherme reactie
endothermic in Norwegian: Endoterm reaksjon
endothermic in Norwegian Nynorsk: Endoterm reaksjon
endothermic in Polish: Reakcja endotermiczna
endothermic in Portuguese: Endergónica
endothermic in Russian: Эндотермические реакции
endothermic in Finnish: Endoterminen reaktio
endothermic in Swedish: Endoterm
endothermic in Turkish: Isıalan
endothermic in Ukrainian: Ендотермічна реакція
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