Faraday constant

Michael Faraday (1791-1867)

Faraday constant

The Faraday constant, denoted by the symbol F, is a fundamental physical constant representing the magnitude of electric charge per mole of electrons. It is named after the English scientist Michael Faraday, who made significant contributions to the fields of electromagnetism and electrochemistry. The Faraday constant is crucial in the study of electrochemistry and is used in various calculations involving electrolysis and electrochemical cells.

Value

The Faraday constant is defined as the product of the Avogadro constant (N_A) and the elementary charge (e). Its value is approximately: \[ F = 96485.33212 \, \text{C/mol} \] where:

• C is the coulomb, the unit of electric charge.
• mol is the mole, the unit of amount of substance.

Applications

The Faraday constant is used in several key equations and principles in electrochemistry, including:

• Faraday's laws of electrolysis: These laws quantify the relationship between the amount of substance altered at an electrode during electrolysis and the quantity of electric charge passed through the electrolyte.
• Nernst equation: This equation relates the reduction potential of a half-cell in an electrochemical cell to the standard electrode potential, temperature, and activities (or concentrations) of the chemical species involved.
• Electrochemical equivalent: The mass of a substance deposited or dissolved during electrolysis is proportional to the quantity of electricity passed and can be calculated using the Faraday constant.

Historical Context

The concept of the Faraday constant emerged from Michael Faraday's experiments in the early 19th century. Faraday's work laid the foundation for the field of electrochemistry, and his laws of electrolysis were among the first quantitative relationships in chemistry.

Related Concepts

• Electrochemical cell
• Electrolysis
• Faraday's laws of electrolysis
• Nernst equation
• Avogadro constant
• Elementary charge

See Also

• Michael Faraday
• Electrochemistry
• Coulomb
• Mole (unit)