Faraday Constant - Wikipedia

Physical constant: Electric charge of one mole of electrons Not to be confused with farad.

Faraday constant
Michael Faraday, the constant's namesake
Common symbols	F
SI unit	coulomb per mole (C/mol)
In SI base units	s⋅A⋅mol−1
Derivations fromother quantities	F = eNA
Value	96485.3321233100184 C/mol

In physical chemistry, the Faraday constant (symbol F, sometimes stylized as ℱ) is a physical constant defined as the quotient of the total electric charge (q) by the amount (n) of elementary charge carriers in any given sample of matter: F = q/n; it is expressed in units of coulombs per mole (C/mol). As such, it represents the "molar elementary charge",[1] that is, the electric charge of one mole of elementary carriers (e.g., protons). It is named after the English scientist Michael Faraday. Since the 2019 revision of the SI,[1] the Faraday constant has an exactly defined value, the product of the elementary charge (e, in coulombs) and the Avogadro constant (NA, in reciprocal moles):

F = e × NA = 9.64853321233100184×104 C/mol.

Derivation

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The Faraday constant can be thought of as the proportionality factor between the charge in coulombs (used in physics and in practical electrical measurements) and the amount of substance in moles (used in chemistry), and is therefore of particular use in electrochemistry, particularly in electrolysis calculations. Because the elementary charge is exactly 1.602176634×10−19 C,[1] and there are exactly NA = 6.02214076×1023 entities per mole,[1] the Faraday constant is given by the product of these two quantities:

F = e × NA   = 1.602176634×10−19 C × 6.02214076×1023 mol−1   = 9.64853321233100184×104 C/mol.

The value of F was first determined in the 1800s by weighing the amount of silver deposited in an electrochemical reaction, in which a measured current was passed for a measured time, and using Faraday's law of electrolysis.[2] Until about 1970, the most reliable value of the Faraday constant was determined by a related method of electro-dissolving silver metal in perchloric acid.[3]

Other common units

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

Faraday – a unit of charge

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Related to the Faraday constant is the "faraday", a unit of electrical charge. Its use is much less common than of the coulomb, but is sometimes used in electrochemistry.[4] One faraday of charge is the charge of one mole of elementary charges (or of negative one mole of electrons), that is,

1 faraday = F × 1 mol = 9.64853321233100184×104 C = N0 × e = 6.02214076×1023 e.

Where N0 is Avogadro's number, the unitless counterpart to NA. Conversely, the Faraday constant F equals 1 faraday per mole. The farad is an unrelated unit of capacitance, 1 farad = 1 coulomb / 1 volt.

See also

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• Farad, the unit of electrical capacitance
• Faraday efficiency
• Faraday's laws of electrolysis
• Faraday cup

References

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1. ^ a b c d Newell, David B.; Tiesinga, Eite (2019). The International System of Units (SI). NIST Special Publication 330. Gaithersburg, Maryland: National Institute of Standards and Technology. doi:10.6028/nist.sp.330-2019. S2CID 242934226.
2. ^ NIST Introduction to physical constants
3. ^ IUPAC (1976). "Status of the Faraday constant as an analytical standard". Pure and Applied Chemistry. 45 (2): 125–130. doi:10.1351/pac197645020125.
4. ^ Foundations of Physics, Volume 2, by R. S. Gambhir, 1993, p. 51

v t e Scientists whose names are used in physical constants
Physical constants	Isaac Newton (Newtonian constant of gravitation) Amedeo Avogadro (Avogadro constant) Michael Faraday (Faraday constant) Johann Josef Loschmidt (Loschmidt constant) Johann Jakob Balmer Josef Stefan (Stefan–Boltzmann constant) Ludwig Boltzmann (Boltzmann constant, Stefan–Boltzmann constant) Johannes Rydberg (Rydberg constant) J. J. Thomson Max Planck (Planck constant) Wilhelm Wien Otto Sackur Niels Bohr (Bohr radius) Edwin Hubble (Hubble constant) Hugo Tetrode Douglas Hartree Brian Josephson (Josephson constant) Klaus von Klitzing (von Klitzing constant)
List of scientists whose names are used as SI units and non SI units

v t e Michael Faraday
Physics	Faraday's law of induction Faraday effect Faraday cage Faraday constant Farad Faraday cup Faraday's laws of electrolysis Faraday paradox Faraday rotator Faraday-efficiency effect Faraday wave Faraday's ice pail experiment Faraday efficiency Electrochemistry Faraday disc Line of force
Lectures	Royal Institution Christmas Lectures The Chemical History of a Candle
Related	Michael Faraday Memorial Faraday Building Faraday Building (Manchester) Faraday (crater) Faraday Future IET Faraday Medal Royal Society of London Michael Faraday Prize Institute of Physics Michael Faraday Medal and Prize Faraday Medal (electrochemistry) Faraday Lectureship Prize
Category:Michael Faraday

v t e Mole concepts
Constants	Avogadro constant Boltzmann constant Gas constant Faraday constant Molar mass constant
Physical quantities	Mass concentration Molar concentration Molality Mass Volume Density Mole fraction Mass fraction Amount of substance Molar mass Atomic mass Particle number Pressure Thermodynamic temperature Molar volume Specific volume
Laws	Charles's law Boyle's law Gay-Lussac's law Combined gas law Avogadro's law Ideal gas law