Molar mass In chemistry, the molar mass M is a physical property defined as the mass of a given substance (chemical element or chemical compound) divided by its amount of substance. The base SI unit for molar mass is kg/mol. However, for historical reasons, molar masses are almost always expressed in g/mol. [Wikipedia: https://en.wikipedia.org/wiki/Molar_mass] Chemistry QUDT http://qudt.org/vocab/quantity#MolarMass <http://dbpedia.org/resource/Molar_mass> ODM2 Units Type Controlled Vocabulary ODM2 Working Group A vocabulary for describing the type of the Unit or the more general quantity that the Unit represents.