In simple terms, molar mass of a substance is the total weight of that substance (in either kilogram or gram) for one mole of that substance. That is, the weight of a substance for 6.02214076×1023 molecules or atoms of that substance.
Gram atomic mass is another term for the mass, in grams, of one mole of atoms of that element. “Gram atom” is a former term for a mole.
The term formula weight (F.W.) has a specific meaning when used in the context of DNA synthesis: whereas an individual phosphoramidite nucleobase to be added to a DNA polymer has protecting groups and has its molecular weight quoted including these groups, the amount of molecular weight that is ultimately added by this nucleobase to a DNA polymer is referred to as the nucleobase’s formula weight (i.e., the molecular weight of this nucleobase within the DNA polymer, minus protecting groups).
^ a b Mohr, Peter J.; Taylor, Barry N.; Newell, David B. (2011). “CODATA Recommended Values of the Fundamental Physical Constants: 2010”. Database developed by J. Baker, M. Douma, and S. Kotochigova. National Institute of Standards and Technology, Gaithersburg, MD 20899.
^ International Union of Pure and Applied Chemistry (1984). “Note on the terminology for molar masses in polymer science”. J. Polym. Sci., Polym. Lett. Ed. 22 (1): 57. Bibcode:1984JPoSL..22…57.. doi:10.1002/pol.1984.130220116.
^ “Atomic Weights and Isotopic Compositions for All Elements”. NIST. Retrieved 2007-10-14.
^ “Author Guidelines – Article Layout”. RSC Publishing. Retrieved 2007-10-14.
^ Possolo, Antonio; van der Veen, Adriaan M. H.; Meija, Juris; Hibbert, D. Brynn (2018-01-04). “Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report)”. doi:10.1515/pac-2016-0402. Retrieved 2018-09-23.