Aspect. Molar Mass. Percent Composition. Definition. The mass of one mole of a substance. The percentage by mass of each element in a compound. Unit. Grams per mole (g/mol).

The molar mass is also used to calculate the percent composition of an element. These two terms are explained here. Read the complete article for more information.

Molecular Mass of Elements. Molecular mass is the sum of the atomic masses of all the atoms in a molecule. For instance, the molecular mass of water (H₂O) ...