Chemical decomposition: Difference between revisions
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[[File:Chemical decomposition.gif|thumb|Chemical decomposition]]{{Short description|Breakdown of a chemical species into two or more parts; reverse process of a synthesis reaction}} |
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[[Image:Chemical decomposition.gif|right|thumb]] |
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'''Chemical decomposition''', or '''chemical breakdown''', is the process or effect of simplifying a single [[molecular entity|chemical entity]] (normal molecule, [[reaction intermediate]], etc.) into two or more fragments.<ref>{{GoldBookRef |title=chemical decomposition |file=C01020 }}</ref> Chemical decomposition is usually regarded and defined as the exact opposite of [[chemical synthesis]]. In short, the chemical reaction in which two or more products are formed from a single reactant is called a decomposition reaction. |
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The details of a decomposition process are not always well defined. Nevertheless, some activation energy is generally needed to break the involved bonds and as such, higher temperatures generally accelerates decomposition. The net reaction can be an [[endothermic process]], or in the case of spontaneous decompositions, an [[exothermic process]]. |
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'''Chemical decomposition''' or '''analysis''' is the separation of a [[chemical compound]] into [[chemical element|elements]] or smaller compounds. It is sometimes defined as the exact opposite of a [[chemical synthesis]]. Chemical decomposition is often an undesired [[chemical reaction]]. The stability that a chemical compound ordinarily has is eventually limited when exposed to extreme environmental conditions like [[heat]], [[radiation]], [[humidity]] or the [[acidity]] of a [[solvent]]. The details of decomposition processes are generally not well defined, as a [[molecule]] may break up into a host of smaller fragments. Chemical decomposition is exploited in several analytical techniques, notably [[mass spectrometry]], traditional [[gravimetric analysis]], and [[thermogravimetric analysis]]. |
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The stability of a chemical compound is eventually limited when exposed to extreme environmental conditions such as [[heat]], [[radiation]], [[humidity]], or the [[acidity]] of a [[solvent]]. Because of this chemical decomposition is often an undesired [[chemical reaction]]. However chemical decomposition can be desired, such as in various waste treatment processes. |
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A broader definition of the term '''decomposition''' also includes the breakdown of one phase into two or more phases.<ref name="Gold">{{GoldBookRef|title=decomposition|url=http://goldbook.iupac.org/D01547.html}}</ref> |
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For example, this method is employed for several analytical techniques, notably [[mass spectrometry]], traditional [[gravimetric analysis]], and [[thermogravimetric analysis]]. Additionally decomposition reactions are used today for a number of other reasons in the production of a wide variety of products. One of these is the explosive breakdown reaction of [[sodium azide]] [(NaN<sub>3</sub>)<sub>2</sub>] into nitrogen gas (N<sub>2</sub>) and sodium (Na). It is this process which powers the life-saving airbags present in virtually all of today's automobiles.<ref>{{Cite web|url=https://prezi.com/1idm8hytmsni/chemical-reactions-in-everyday-life/|title=Chemical reactions in Everyday life|website=prezi.com|language=en|access-date=2017-05-01}}</ref> |
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There are broadly 3 types of decomposition reactions: thermal, electrolytic and catalytic.{{Fact|date=March 2009}} |
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Decomposition reactions can be generally classed into three categories; thermal, electrolytic, and photolytic decomposition reactions.<ref>{{Cite web|url=https://amrita.olabs.edu.in/?sub=73&brch=3&sim=80&cnt=1|title=Decomposition Reactions}}</ref> |
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==Reaction formula== |
==Reaction formula== |
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In the breakdown of a compound into its constituent parts, the generalized reaction for chemical decomposition is: |
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: AB → A + B (AB represents the reactant that begins the reaction, and A and B represent the products of the reaction) |
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: AB → A + B |
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An example is the [[electrolysis]] of [[water (molecule)|water]] to the gases [[hydrogen]] and [[oxygen]]: |
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: 2 H<sub>2</sub>O({{serif|l}}) → 2 H<sub>2</sub>({{serif|g}}) + O<sub>2</sub>({{serif|g}}) |
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===Additional examples=== |
===Additional examples=== |
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[[File:13. Каталитичко разложување на водород пероксид.webm|thumb|right|280px|An experiment describing catalytic decomposition of hydrogen peroxide, with {{Chem2|[[MnO2]]}} as catalyst. A concentrated hydrogen peroxide solution can be easily decomposed to water and oxygen.]] |
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An example of spontaneous decomposition is that of [[hydrogen peroxide]] |
An example of a spontaneous (''without'' addition of an external energy source) decomposition is that of [[hydrogen peroxide]] which slowly decomposes into water and oxygen <small>(see video at right</small>): |
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: 2 H<sub>2</sub>O<sub>2</sub> → 2 H<sub>2</sub>O + O<sub>2</sub> |
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This reaction is one of the exceptions to the endothermic nature of decomposition reactions. |
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Other reactions involving decomposition do require the input of external energy. This energy can be in the form of heat, radiation, electricity, or light. The latter being the reason some chemical compounds, such as many prescription medicines, are kept and stored in dark bottles which reduce or eliminate the possibility of light reaching them and initiating decomposition. |
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[[Carbonate]]s will decompose when heated, a notable exception being that of [[carbonic acid]], H<sub>2</sub>CO<sub>3</sub>. Carbonic acid, the "fizz" in sodas, pop cans and other carbonated beverages, will decompose over time (spontaneously) into [[carbon dioxide]] and water |
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When heated, [[carbonate]]s will decompose. A notable exception is [[carbonic acid]], (H<sub>2</sub>CO<sub>3</sub>).<ref>{{Cite web|url=https://ibburke.wordpress.com/2011/03/27/decomposition-of-carbonic-acid/|title=Decomposition of Carbonic Acid Culminating by Elizabeth Burke|last=ibburke|date=2011-03-27|website=ibburke|access-date=2017-03-04}}</ref> Commonly seen as the "fizz" in carbonated beverages, carbonic acid will spontaneously decompose over time into [[carbon dioxide]] and water. The reaction is written as: |
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Other carbonates will decompose when heated producing the corresponding [[metal]] [[oxide]] and carbon dioxide. In the following equation ''M'' represents a metal: |
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Other carbonates will decompose when heated to produce their corresponding [[metal]] [[oxide]] and carbon dioxide.<ref>{{Cite web|url=https://Quizlet.com//|title=Synthesis and Decomposition Reactions|last=Walker|first=MS|year=2016|website=Quizlet.com/MSWalker22|series=Online Series in Organic Chemistry|language=en|type=Audio-Video Online Lecture|orig-year=Available now|access-date=2017-03-04|url-access=registration }}</ref> The following equation is an example, where ''M'' represents the given metal: |
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: ''M''CO<sub>3</sub> → ''M''O + CO<sub>2</sub> |
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Metal [[chlorate]]s also decompose when heated. |
Metal [[chlorate]]s also decompose when heated. In this type of decomposition reaction, a metal [[chloride]] and oxygen gas are the products. Here, again, ''M'' represents the metal: |
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: 2 ''M''ClO<sub>3</sub> → 2 ''M''Cl+ 3 O<sub>2</sub> |
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A common decomposition of a chlorate |
A common decomposition of a chlorate is in the reaction of [[potassium chlorate]] where oxygen is the product. This can be written as: |
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: 2 KClO<sub>3</sub> → 2 KCl + 3 O<sub>2</sub> |
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==See also== |
==See also== |
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{{wiktionary|Chemical decomposition}} |
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* [[Analytical chemistry]] |
* [[Analytical chemistry]] |
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* [[Thermal decomposition]] |
* [[Thermal decomposition]] |
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==References== |
==References== |
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{{reflist}} |
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<references/> |
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==External links== |
==External links== |
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{{wiktionary}} |
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{{commons category}} |
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* https://quizlet.com/42968634/types-of-decomposition-reactions-flash-cards/ PDF |
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{{Authority control}} |
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[[Category:Inorganic chemistry]] |
[[Category:Inorganic chemistry]] |
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[[Category:Organic chemistry]] |
[[Category:Organic chemistry]] |
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[[Category:Chemical reactions]] |
[[Category:Chemical reactions]] |
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{{chem-stub}} |
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[[cs:Chemodegradace]] |
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[[de:Zersetzung (Chemie)]] |
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[[el:Θερμική διάσπαση]] |
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[[it:Decomposizione (chimica)]] |
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[[nl:Ontleding (scheikunde)]] |
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[[ja:化学分解]] |
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[[pt:Reação de decomposição]] |
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[[sq:Reaksioni i analizës (shpërbërjes)]] |
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[[th:ปฏิกิริยาแตกตัว]] |
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[[zh-yue:分解反應]] |
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[[zh:分解反应]] |
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Latest revision as of 08:33, 10 July 2024
Chemical decomposition, or chemical breakdown, is the process or effect of simplifying a single chemical entity (normal molecule, reaction intermediate, etc.) into two or more fragments.[1] Chemical decomposition is usually regarded and defined as the exact opposite of chemical synthesis. In short, the chemical reaction in which two or more products are formed from a single reactant is called a decomposition reaction.
The details of a decomposition process are not always well defined. Nevertheless, some activation energy is generally needed to break the involved bonds and as such, higher temperatures generally accelerates decomposition. The net reaction can be an endothermic process, or in the case of spontaneous decompositions, an exothermic process.
The stability of a chemical compound is eventually limited when exposed to extreme environmental conditions such as heat, radiation, humidity, or the acidity of a solvent. Because of this chemical decomposition is often an undesired chemical reaction. However chemical decomposition can be desired, such as in various waste treatment processes.
For example, this method is employed for several analytical techniques, notably mass spectrometry, traditional gravimetric analysis, and thermogravimetric analysis. Additionally decomposition reactions are used today for a number of other reasons in the production of a wide variety of products. One of these is the explosive breakdown reaction of sodium azide [(NaN3)2] into nitrogen gas (N2) and sodium (Na). It is this process which powers the life-saving airbags present in virtually all of today's automobiles.[2]
Decomposition reactions can be generally classed into three categories; thermal, electrolytic, and photolytic decomposition reactions.[3]
Reaction formula
[edit]In the breakdown of a compound into its constituent parts, the generalized reaction for chemical decomposition is:
- AB → A + B (AB represents the reactant that begins the reaction, and A and B represent the products of the reaction)
An example is the electrolysis of water to the gases hydrogen and oxygen:
- 2 H2O(l) → 2 H2(g) + O2(g)
Additional examples
[edit]An example of a spontaneous (without addition of an external energy source) decomposition is that of hydrogen peroxide which slowly decomposes into water and oxygen (see video at right):
- 2 H2O2 → 2 H2O + O2
This reaction is one of the exceptions to the endothermic nature of decomposition reactions.
Other reactions involving decomposition do require the input of external energy. This energy can be in the form of heat, radiation, electricity, or light. The latter being the reason some chemical compounds, such as many prescription medicines, are kept and stored in dark bottles which reduce or eliminate the possibility of light reaching them and initiating decomposition.
When heated, carbonates will decompose. A notable exception is carbonic acid, (H2CO3).[4] Commonly seen as the "fizz" in carbonated beverages, carbonic acid will spontaneously decompose over time into carbon dioxide and water. The reaction is written as:
- H2CO3 → H2O + CO2
Other carbonates will decompose when heated to produce their corresponding metal oxide and carbon dioxide.[5] The following equation is an example, where M represents the given metal:
- MCO3 → MO + CO2
A specific example is that involving calcium carbonate:
- CaCO3 → CaO + CO2
Metal chlorates also decompose when heated. In this type of decomposition reaction, a metal chloride and oxygen gas are the products. Here, again, M represents the metal:
- 2 MClO3 → 2 MCl+ 3 O2
A common decomposition of a chlorate is in the reaction of potassium chlorate where oxygen is the product. This can be written as:
- 2 KClO3 → 2 KCl + 3 O2
See also
[edit]References
[edit]- ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "chemical decomposition". doi:10.1351/goldbook.C01020
- ^ "Chemical reactions in Everyday life". prezi.com. Retrieved 2017-05-01.
- ^ "Decomposition Reactions".
- ^ ibburke (2011-03-27). "Decomposition of Carbonic Acid Culminating by Elizabeth Burke". ibburke. Retrieved 2017-03-04.
- ^ Walker, MS (2016) [Available now]. "Synthesis and Decomposition Reactions". Quizlet.com/MSWalker22 (Audio-Video Online Lecture). Online Series in Organic Chemistry. Retrieved 2017-03-04.
External links
[edit]
