Mole (unit)

Mole (unit)

The mole is a unit of measurement used in chemistry to express amounts of a chemical substance, defined as exactly 6.02214076×10^23 particles, which may be atoms, molecules, ions, or electrons.

Definition

In the International System of Units (SI), the mole is the unit of amount of substance. One mole contains exactly 6.02214076×10^23 elementary entities. This number is the fixed numerical value of the Avogadro constant, expressed in mol^−1, in the International System of Units (SI).

History

The term "mole" was first used in a textbook by Fritz Haber and Max Born in 1905. It was officially adopted into the International System of Units (SI) in 1971.

Molar mass

The molar mass of a substance is the mass of one mole of that substance. It is usually measured in g/mol. For example, the molar mass of water is approximately 18.015 g/mol.

Mole Day

Mole Day is an unofficial holiday celebrated among chemists in the United States and Canada on October 23, in honor of the Avogadro constant.

See also

• Avogadro's law
• Molar concentration
• Molar volume
• Molar mass
• Mole Day

External links

• Definition of the mole (SI Brochure)

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