Title: amount fraction
Long Title: IUPAC Gold Book - amount fraction
DOI: 10.1351/goldbook.A00296
Status: current
Index: quantity

Definition
Amount of a constituent divided by the total amount of all constituents in the mixture. It is also called mole fraction. Amount fraction is equal to the 'number fraction': the number of entities of one constituent divided by the total number of entities in the mixture.

Related Terms
- constituent: https://goldbook.iupac.org//terms/view/C01281
- entities: https://goldbook.iupac.org//terms/view/M03986
- fraction: https://goldbook.iupac.org//terms/view/F02494
- number of entities: https://goldbook.iupac.org//terms/view/N04266

Source
- Green Book, 2nd ed., p. 41 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/A00296/html
- json: https://goldbook.iupac.org/terms/view/A00296/json
- xml: https://goldbook.iupac.org/terms/view/A00296/xml

Citation: Citation: 'amount fraction' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.A00296
License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.
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Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.
Accessed: 2026-04-26T09:56:03+00:00