Quantities and Units
| Quantity | Unit | Remarks | |||
|---|---|---|---|---|---|
| Name | Symbol | Definition | Name | Symbol | |
| relative atomic mass | Ar | Ratio of the average mass per atom of an element to 1/12 of the mass of an atom of the nuclide 12C | one | 1 | Formerly called atomic/molecular weight. Example: Ar(Cl) = 35.453. Both quantities depend on the nuclidic composition. |
| relative molecular mass | Mr | Ratio of the average mass per molecule or specified entity of a substance to 1/12 of the mass of an atom of the nuclide 12C | |||
| number of molecules or other elementary entities | N | Number of molecules or other elementary entities in a system | one | 1 | |
| amount of substance | n, (ν) | mole | mol | The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kg of 12C. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specific groups of such particles. The definition applies to unbound atoms of 12C, at rest and in their ground state. | |
| ... | |||||
Read more about this topic: ISO 31-8
Famous quotes containing the words quantities and/or units:
“James Brown and Frank Sinatra are two different quantities in the universe. They represent two different experiences of the world.”
—Imamu Amiri Baraka [Everett Leroi Jones] (b. 1934)
“Even in harmonious families there is this double life: the group life, which is the one we can observe in our neighbour’s household, and, underneath, another—secret and passionate and intense—which is the real life that stamps the faces and gives character to the voices of our friends. Always in his mind each member of these social units is escaping, running away, trying to break the net which circumstances and his own affections have woven about him.”
—Willa Cather (1873–1947)