Volta potential
Encyclopedia
Volta potential in electrochemistry
, is the electric potential difference between two points ("1" and "2") in the vacuum:
where M1 and M2 are two uncharged metals brought into contact.
The Volta potential is named after Alessandro Volta
.
to the metal with the higher work function until the electrochemical potential of the electrons in the bulk of both phases are equal. The actual numbers of electrons that passes between the two phases is small, and the occupancy of the Fermi level
s is practically unaffected.
of an electrostatic capacitor
, the two sides of which are made of the two metals for which the Volta potential difference is measured and the electrical charge used to load the capacitor. The Volta potential difference between a metal and an electrolyte can be measured in a similar fashion.
Electrochemistry
Electrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
, is the electric potential difference between two points ("1" and "2") in the vacuum:
- point "1" close to the surface of metal M1;
- point "2" close to the surface of metal M2 (or electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
);
where M1 and M2 are two uncharged metals brought into contact.
The Volta potential is named after Alessandro Volta
Alessandro Volta
Count Alessandro Giuseppe Antonio Anastasio Gerolamo Umberto Volta was a Lombard physicist known especially for the invention of the battery in 1800.-Early life and works:...
.
Volta potential between two metals
When two metals are electrically isolated from each other, an arbitrary potential difference may exist between them. However, when two different metals are brought into contact, electrons will flow from the metal with a lower work functionWork function
In solid-state physics, the work function is the minimum energy needed to remove an electron from a solid to a point immediately outside the solid surface...
to the metal with the higher work function until the electrochemical potential of the electrons in the bulk of both phases are equal. The actual numbers of electrons that passes between the two phases is small, and the occupancy of the Fermi level
Fermi level
The Fermi level is a hypothetical level of potential energy for an electron inside a crystalline solid. Occupying such a level would give an electron a potential energy \epsilon equal to its chemical potential \mu as they both appear in the Fermi-Dirac distribution function,which...
s is practically unaffected.
Measurement of Volta potential
The Volta potential difference is measurable. It is related to the capacitanceCapacitance
In electromagnetism and electronics, capacitance is the ability of a capacitor to store energy in an electric field. Capacitance is also a measure of the amount of electric potential energy stored for a given electric potential. A common form of energy storage device is a parallel-plate capacitor...
of an electrostatic capacitor
Capacitor
A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...
, the two sides of which are made of the two metals for which the Volta potential difference is measured and the electrical charge used to load the capacitor. The Volta potential difference between a metal and an electrolyte can be measured in a similar fashion.
See also
- Electrode potentialElectrode potentialElectrode potential, E, in electrochemistry, according to an IUPAC definition, is the electromotive force of a cell built of two electrodes:* on the left-hand side is the standard hydrogen electrode, and...
- Absolute electrode potentialAbsolute electrode potentialAbsolute electrode potential, in electrochemistry, according to an IUPAC definition, is the electrode potential of a metal measured with respect to a universal reference system .-Definition:...
- Electrical potential
- Galvani potentialGalvani potentialGalvani potential in electrochemistry, is the electric potential difference between two points in the bulk of two phases...
- Potential difference (voltage)
- VoltVoltThe volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...