Term: amount fraction x (y for gaseous mixtures)
https://doi.org/10.1351/goldbook.A00296

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:
1) fraction (http://doi.org/10.1351/goldbook.F02494).
2) constituent (http://doi.org/10.1351/goldbook.C01281).
3) number fraction (http://doi.org/10.1351/goldbook.N04265).
4) number of entities (http://doi.org/10.1351/goldbook.N04266).
5) entities (http://doi.org/10.1351/goldbook.M03986).

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

Citation: 'amount fraction <em>x</em> (<em>y</em> for gaseous mixtures)' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.A00296

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