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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. According to the IUPAC definition, [4] it is the partial molar Gibbs energy of the substance at the specified electric potential, where the substance is in a specified ...
Bipolar electrochemistry scheme. In electrochemistry, standard electrode potential, or , is a measure of the reducing power of any element or compound.The IUPAC "Gold Book" defines it as; "the value of the standard emf (electromotive force) of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-hand electrode".
Particles tend to move from higher chemical potential to lower chemical potential because this reduces the free energy. In this way, chemical potential is a generalization of "potentials" in physics such as gravitational potential. When a ball rolls down a hill, it is moving from a higher gravitational potential (higher internal energy thus ...
However, the corresponding Gibbs free energy changes (∆G°) must satisfy ∆G° = – z FE°, where z electrons are transferred, and the Faraday constant F is the conversion factor describing Coulombs transferred per mole electrons. Those Gibbs free energy changes can be added.
To avoid possible ambiguities, the electrode potential thus defined can also be referred to as Gibbs–Stockholm electrode potential. In both conventions, the standard hydrogen electrode is defined to have a potential of 0 V. Both conventions also agree on the sign of E for a half-cell reaction when it is written as a reduction.
According to a more specific definition presented by Trasatti, [2] the absolute electrode potential is the difference in electronic energy between a point inside the metal (Fermi level) of an electrode and a point outside the electrolyte in which the electrode is submerged (an electron at rest in vacuum). This potential is difficult to ...
References and notes CH 3 COOH + 2H + + 2e − → CH 3 CHO + H 2 O: −0.58 Many carboxylic acid: aldehyde redox reactions have a potential near this value 2 H + + 2 e − → H 2: −0.41 Non-zero value for the hydrogen potential because at pH = 7, [H +] = 10 −7 M and not 1 M as in the standard hydrogen electrode (SHE), and that: E red = -0 ...
The electrochemical window (EW) is an important concept in organic electrosynthesis and design of batteries, especially organic batteries. [5] This is because at higher voltage (greater than 4.0 V) organic electrolytes decompose and interferes with the oxidation and reduction of the organic cathode/anode materials.