'Chemical decomposition' or 'analysis' is the fragmentation of a
chemical compound into
elements or smaller compounds. It is sometimes defined as the 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.
A broader definition of the term 'decomposition' also includes the breakdown of one phase into two or more phases.
[1]
Reaction formulas
The generalized reaction formula for chemical decomposition is:
: AB → A + B
with a specific example being the
electrolysis of
water to gaseous
hydrogen and
oxygen:
: 2H
2O → 2H
2 + O
2
Additional examples
An example of spontaneous decomposition is that of
hydrogen peroxide, which will slowly decompose into water and oxygen:
: 2H
2O
2 → 2H
2O + O
2
Carbonates will decompose when heated, a notable exception being that of
carbonic acid, H
2CO
3. Carbonic acid, the "fizz" in sodas, pop cans and other carbonated beverages, will decompose over time (spontaneously) into
carbon dioxide and water:
: H
2CO
3 → H
2O + CO
2
Other carbonates will decompose when heated producing the corresponding
metal oxide and carbon dioxide. In the following equation ''M'' represents a metal:
: MCO
3 → MO + CO
2
A specific example of this involving
calcium carbonate:
: CaCO
3 → CaO + CO
2
Metal
chlorates also decompose when heated. A metal
chloride and oxygen gas are the products.
: MClO
3 → MCl + O
2
A common decomposition of a chlorate to evolve oxygen utilizes
potassium chlorate as follows:
: 2 KClO
3 → 2 KCl + 3 O
2
See also
★
Analytical chemistry
References
1.
External links
★
Biodegradation database
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