Mole (unit) containing of hydrogen atoms in it, weighing exactly 1.008 grams (same as the Ar of one hydrogen atom). The molar mass of a substance is the mass of a sample divided by the amount of substance in that sample. This is a constant for any given substance. Since the unified atomic mass unit (symbol: u, or Da) is defined as 1/12 of the mass of the C atom, it follows that the molar mass of a substance, measured in grams per mole, is numerically equal to its mean atomic or molecular mass expressed in Da. One can determine the amount
International unit that substance is officially abandoned in favor of a newly established mass. International unit In pharmacology, the international unit is a unit of measurement for the amount of a substance; the mass or volume that constitutes one international unit varies based on which substance is being measured, and the variance is based on the biological activity or effect, for the purpose of easier comparison across substances. International units are used to quantify vitamins, hormones, some medications, vaccines, blood products, and similar biologically active substances. The name international unit has often been capitalized (in English and other languages), although major English-language