Convert mass to amount of substance using n = m / M (molar mass).
已知物质的质量与摩尔质量，求物质的量（摩尔数）。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Amount of substance | n = m / M, with m the mass and M the molar mass | IUPAC, Compendium of Chemical Terminology (Gold Book) |
| Molar mass | Obtained by summing the relative atomic masses over the formula | IUPAC, Compendium of Chemical Terminology (Gold Book) |
| Unit | The SI unit of amount of substance is the mole (mol) | BIPM, The International System of Units (SI Brochure, 9th ed., 2019) |
| Relation to particle number | N = n · N_A, where N is the number of elementary entities | BIPM, The International System of Units (SI Brochure, 9th ed., 2019) |
Constants used on this page and their authoritative sources, for verification and citation
| Constant | Value | Unit | Source |
|---|---|---|---|
| Avogadro constant N_A | 6.02214076e23 | mol⁻¹ | SI defining constant (exact, fixed since 2019) |
| Atomic mass constant (1 u) | 1.66053906660e-27 | kg | CODATA 2018 (= 1 g / N_A) |
Note: molar masses M follow the IUPAC standard atomic weights (2021); use exact isotopic masses for monoisotopic samples.