Electrochemical potential
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In [[electrochemistry]], the '''electrochemical potential''', <math>\bar{\mu}</math>, sometimes confusingly abbreviated to ECP, is a [[thermodynamic]] measure that combines the concepts of energy stored in the form of [[chemical potential]] and [[electric charge|electrostatics]]. It is important in biological processes that involve [[molecule|molecular]] [[diffusion]] across membranes, in electroanalytical chemistry, and industrial applications such as batteries and fuel cells. It represents one of the many interchangeable forms of [[potential energy]] through which energy may be [[conservation of energy|conserved]]. Electrochemical potential is expressed in the unit of [[Joule|J]]/[[Mole (unit)|mol]].
In generic terms, electrochemical potential is the [[mechanical work]] done in bringing 1 mole of an ion from a [[standard state]] to a specified [[concentration]] and [[electrical potential]]. By an [[IUPAC]] definition<ref>IUPAC Gold Book, http://goldbook.iupac.org/E01945.html</ref>, it is the partial molar Gibbs energy of the substance at the specified electric potential, where the substance is in a specified phase. Electrochemical potential can be expressed as
:<math>\bar{\mu}_i=\mu_i + z_iF\Phi</math>,
where <math>\mu_i</math> is the [[chemical potential]], <math>z_i</math> is the valency of the ion, <math>F</math> is Faraday's constant, and <math>\Phi</math> is electrostatic potential.
In [[cell membranes]], the electrochemical potential is the sum of the [[chemical potential]] and the [[membrane potential]].
==Incorrect usage==
The term ''electrochemical potential'' is sometimes used in the meaning of electrode potential (either of a corroding electrode, an electrode with a non-zero net reaction, or an electrode at equilibrium). Such a usage can lead to confusion. The measured electrode potential does not equal the change of the electrochemical potential (see [[Galvani potential]]). Therefore, the recent literature usually expands the abbreviation ECP as "electrochemical corrosion potential". For electrode at equilibrium, the phrase of equilibrium or reversible potential of the electrode is used.
==See also==
[[Electrochemical gradient]]
==External links==
[http://www.life.uiuc.edu/crofts/bioph354/lect9.html Electrochemical potential] - lecture notes from University of Illinois at Urbana-Champaign
==References==
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[[category:electrochemistry]]
[[category:thermodynamics]]
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[[fr:potentiel électrochimique]]
[[hu:Elektrokémiai potenciál]]
[[it:Potenziale elettrochimico]]
[[ja:電子化学ポテンシャル]]
[[pl:Potencjał elektrochemiczny]]