Mole and amount of substance
The mole counts specified entities using the exact Avogadro constant.
Key knowledge
The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.02214076 × 10²³ specified elementary entities. The amount n and entity count N are related by n = N/N_A, where N_A = 6.02214076 × 10²³ mol⁻¹ exactly.
Values and equations
n = N/N_A
- n
- Amount of substance mol
- N
- Number of specified entities
- N_A
- Avogadro constant, exactly 6.02214076 × 10²³ mol⁻¹
Conditions and scope
- Specify the entities being counted, such as atoms, molecules or ions.
- Amount of substance and mass are different quantities; an exact unit definition does not remove measurement uncertainty.
- N counts the same specified entities whose amount is n.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Exact SI definition and entity-count relation documented by BIPM; not a measurement of a sample.
2026-10-10 · English unit, exact decimal value and specified-entity scope checked against BIPM's mole definition.
Foundational review
2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.
Sources from other places
Agreement within this scope
Exact mole definition and specified-entity count.
The Japanese translation implements the same international SI standard.
National Metrology Institute of Japan, AIST
- 国際単位系(SI)第9版 · Japanese translation, V3.01 JapanJapaneseShared standard
Table 1, printed p13; §2.3.1 mole, printed pp18–19
- 国際単位系(SI)第9版 · Japanese translation, V3.01
Entry details
Permanent link to this entry ↗- Record identity
- chem-mole
- Revision
- core.1
- Structured reference record
- Essential core · first collection