physical chemistry Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistica ...

, the Faraday constant, denoted by the symbol and sometimes stylized as ℱ, is the

electric charge Electric charge is the physical property of matter that causes charged matter to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carried by protons and electrons respe ...

per

mole Mole (or Molé) may refer to: Animals * Mole (animal) or "true mole", mammals in the family Talpidae, found in Eurasia and North America * Golden moles, southern African mammals in the family Chrysochloridae, similar to but unrelated to Talpida ...

of elementary charges. It is named after the English

scientist A scientist is a person who conducts Scientific method, scientific research to advance knowledge in an Branches of science, area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, ...

Michael Faraday Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic inducti ...

. Since the 2019 redefinition of SI base units, which took effect on 20 May 2019, the Faraday constant has the exactly defined value given by the product of the elementary charge ''e'' and

Avogadro constant The Avogadro constant, commonly denoted or , is the proportionality factor that relates the number of constituent particles (usually molecules, atoms or ions) in a sample with the amount of substance in that sample. It is an SI defining c ...

''N''_A: : : :.

Derivation

The Faraday constant can be thought of as the conversion factor between the mole (used in chemistry) and the coulomb (used in physics and in practical electrical measurements), and is therefore of particular use in

electrochemistry Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference, as a measurable and quantitative phenomenon, and identifiable chemical change, with the potential difference as an outco ...

. Because 1 mole contains exactly entities, and 1 coulomb contains exactly elementary charges, the Faraday constant is given by the quotient of these two quantities: :. One common use of the Faraday constant is in electrolysis calculations. One can divide the amount of charge (the current integrated over time) by the Faraday constant in order to find the chemical amount of a substance (in moles) that has been electrolyzed. The value of was first determined by weighing the amount of

silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...

deposited in an electrochemical reaction in which a measured

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...

was passed for a measured time, and using

Faraday's law of electrolysis Faraday's laws of electrolysis are quantitative relationships based on the electrochemical research published by Michael Faraday in 1833. First law Michael Faraday reported that the mass (m) of elements deposited at an electrode is directly prop ...

Other common units

* 96.485 kJ per volt–gram-equivalent * 23.061 kcal per volt–gram-equivalent * 26.801 A·h/mol

Faraday – a unit of charge

Related to the Faraday constant is the "faraday", a unit of

electrical charge Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...

. It is much less common than the coulomb, but is sometimes used in electrochemistry.''Foundations of Physics, Volume 2'', by R. S. Gambhir, 1993, p. 51
/ref> One faraday of charge is the magnitude of the charge of one mole of electrons, i.e., :1 faraday = ''F'' × 1 mol = Conversely, the Faraday constant ''F'' equals 1 faraday per mole. The faraday is not to be confused with the farad, an unrelated unit of

capacitance Capacitance is the capability of a material object or device to store electric charge. It is measured by the change in charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized ar ...

().

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how much he wants for his entire

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inventory. He says "the

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expressed as

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" and Mr. Burns tells Smithers to "just give him Faraday's Constant". The check is written for $96,485.34.

References

{{Michael Faraday Electrochemical concepts Physical constants Michael Faraday Units of electrical charge Units of amount of substance

Derivation

Other common units

Faraday – a unit of charge

Popular media

See also

References