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Amount of Substance

Physical Sciences

In chemistry, the amount of substance in a given sample of matter is defined as a ratio between the number of elementary entities and the Avogadro constant. The cited article calls it one of the seven base quantities of the International System of Units and gives the unit of amount of substance in that system as the mole, a base unit. Since 2019 the mole has been defined such that the value of the Avogadro constant is exactly 6.02214076 times ten to the twenty-third per mole, defining a macroscopic unit convenient for laboratory-scale chemistry. The elementary entities are usually molecules, atoms, ions or ion pairs of a specified kind. Units such as the mole are grouped under this quantity.

Connections

Belongs To

Chemistry, Disciplines
Source Amount of Substance

Quantity Measured By Unit

Mole, Units

Entity-backed identity for the quantity-measured enum value this unit already carries, resolved to a science concept by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The quantity-measured fact itself stays on the unit unchanged.

Studied In

Chemistry, Disciplines
Source Amount of Substance
Sources
Amount of Substance
  • Wikipedia, lead section
    In chemistry, the amount of substance (symbol n) in a given sample of matter is defined as a ratio (n = N/NA) between the number of elementary entities (N) and the Avogadro constant (NA).
  • Belongs To: Chemistry, Lead sentence
    In chemistry, the amount of substance (symbol n) in a given sample of matter is defined as a ratio (n = N/NA) between the number of elementary entities (N) and the Avogadro constant (NA).
  • Studied In: Chemistry, Lead sentence
    In chemistry, the amount of substance (symbol n) in a given sample of matter is defined as a ratio (n = N/NA) between the number of elementary entities (N) and the Avogadro constant (NA).
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