Related Quantities
Molar mass is closely related to the relative molar mass (M
r) of a compound, to the older term formula weight, and to the standard atomic masses of its constituent elements. However, it should be distinguished from the molecular mass (also known as molecular weight), which is the mass of one molecule (of any single isotopic composition) and is not directly related to the atomic mass, the mass of one atom (of any single isotope). The dalton, symbol Da, is also sometimes used as a unit of molar mass, especially in biochemistry, with the definition 1 Da = 1 g/mol, despite the fact that it is strictly a unit of mass (1 Da = 1.660 538 782(83)×10−27 kg).
Molecular weight (M.W.) and formula weight (F.W.) are older terms for what is now more correctly called the relative molar mass (M
r).Nic, M.; Jirat, J.; Kosata, B., eds. (2006–). "relative molar mass". IUPAC Compendium of Chemical Terminology (Online ed.). doi:10.1351/goldbook.{{{file}}}. ISBN 0-9678550-9-8. http://goldbook.iupac.org/R05270.html. This is a dimensionless quantity (i.e., a pure number, without units) equal to the molar mass divided by the molar mass constant.
Read more about this topic: Molar Mass
Famous quotes containing the words related and/or quantities:
“The near explains the far. The drop is a small ocean. A man is related to all nature. This perception of the worth of the vulgar is fruitful in discoveries. Goethe, in this very thing the most modern of the moderns, has shown us, as none ever did, the genius of the ancients.”
—Ralph Waldo Emerson (1803–1882)
“The Walrus and the Carpenter
Were walking close at hand:
They wept like anything to see
Such quantities of sand:
“If this were only cleared away,”
They said, “it would be grand!”
“If seven maids with seven mops
Swept it for half a year,
Do you suppose,” the Walrus said,
“That they could get it clear?”
“I doubt it,” said the Carpenter,
And shed a bitter tear.”
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)