Search results
Results from the WOW.Com Content Network
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".
Faraday's law (also known as the Faraday–Lenz law) states that the electromotive force (EMF) is given by the total derivative of the magnetic flux with respect to time t: =, where is the EMF and Φ B is the magnetic flux through a
In electrochemistry, the Nernst equation is a chemical thermodynamical relationship that permits the calculation of the reduction potential of a reaction (half-cell or full cell reaction) from the standard electrode potential, absolute temperature, the number of electrons involved in the redox reaction, and activities (often approximated by concentrations) of the chemical species undergoing ...
The emf of the cell at zero current is the maximum possible emf. It can be used to calculate the maximum possible electrical energy that could be obtained from a chemical reaction. This energy is referred to as electrical work and is expressed by the following equation:
Therefore, emf is expressed as = (+) where is emf and v is the unit charge velocity. In a macroscopic view, for charges on a segment of the loop, v consists of two components in average; one is the velocity of the charge along the segment v t , and the other is the velocity of the segment v l (the loop is deformed or moved).
Potentiometry passively measures the potential of a solution between two electrodes, affecting the solution very little in the process. One electrode is called the reference electrode and has a constant potential, while the other one is an indicator electrode whose potential changes with the sample's composition.
The EMF of a concentration cell without transport is: E n t = R T F ln a 2 a 1 {\displaystyle E_{\mathrm {nt} }={\frac {RT}{F}}\ln {\frac {a_{2}}{a_{1}}}} where a 1 {\displaystyle a_{1}} and a 2 {\displaystyle a_{2}} are activities of HCl in the two solutions, R {\displaystyle R} is the universal gas constant , T {\displaystyle T} is the ...
In effect, the concentrations are a function of the potential as well. A full treatment, which yields the current as a function of potential only, will be expressed by the extended Butler–Volmer equation, but will require explicit inclusion of mass transfer effects in order to express the concentrations as functions of the potential.