Editing Endothermic process (section)

{{short description|Thermodynamic process that absorbs energy from its surroundings}}
{{About|the physical effect|self-maintained thermal homeostasis|Endotherm}}An '''endothermic process''' is a chemical or physical process that absorbs heat from its surroundings.<ref name=":0">{{Cite web |date=2016-06-27 |title=17.3: Exothermic and Endothermic Processes |url=https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/17%3A_Thermochemistry/17.03%3A_Exothermic_and_Endothermic_Processes |access-date=2024-06-26 |website=Chemistry LibreTexts |language=en}}</ref> In terms of [[thermodynamics]], it is a [[thermodynamic process]] with an increase in the [[enthalpy]] {{mvar|H}} (or [[internal energy]] {{mvar|U}}) of the system.<ref name="Oxtoby8th">Oxtoby, D. W; Gillis, H.P., Butler, L. J. (2015). ''[[iarchive:principlesofmode0000oxto|Principle of Modern Chemistry]]'', Brooks Cole. p. 617.  {{ISBN|978-1305079113}}</ref> In an endothermic process, the heat that a system absorbs is [[thermal energy]] transfer into the system. Thus, an endothermic reaction generally leads to an increase in the [[temperature]] of the system and a decrease in that of the surroundings.<ref name=":0" />

The term was coined by 19th-century French chemist [[Marcellin Berthelot]].<ref>{{Cite web |last=Sutton |first=Mike |date=2007-03-01 |title=Chemistry for the common good |url=https://www.chemistryworld.com/features/chemistry-for-the-common-good/3004535.article |access-date=2024-06-26 |website=Chemistry World |language=en}}</ref> The term ''endothermic'' comes from the [[Greek language|Greek]] ἔνδον (''endon'') meaning 'within' and θερμ- (''therm'') meaning 'hot' or 'warm'.<ref>{{Cite web |title=endothermic {{!}} Etymology of endothermic by etymonline |url=https://www.etymonline.com/word/endothermic |access-date=2024-06-28 |website=www.etymonline.com |language=en}}</ref>

An endothermic process may be a chemical process, such as dissolving [[ammonium nitrate]] ({{chem2|NH4NO3}}) in [[water]] ({{chem2|H2O}}), or a physical process, such as the melting of [[ice]] cubes.<ref>{{Citation |last=Lu |first=Jue Xi |title=Biochemistry, Dissolution and Solubility |date=2024 |work=StatPearls |url=http://www.ncbi.nlm.nih.gov/books/NBK431100/ |access-date=2024-06-28 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=28613752 |last2=Tupper |first2=Connor |last3=Gutierrez |first3=Alejandra V. |last4=Murray |first4=John}}</ref>

The opposite of an endothermic process is an [[exothermic process]], one that releases or "gives out" energy, usually in the form of heat and sometimes as [[electrical energy]].<ref name=":0" /> Thus, ''endo'' in endothermic refers to energy or heat going in, and ''exo'' in exothermic refers to energy or heat going out. In each term (endothermic and exothermic) the prefix refers to where heat (or electrical energy) goes as the process occurs.<ref>{{Cite web |title=Endothermic & Exothermic Reactions |url=https://www.ashrae.org/file%20library/communities/student%20zone/k-12%20activities/ashrae-endothermic---exothermic-reactions-stem-kit.pdf |access-date=2024-06-28 |website=Ashrae}}</ref>