The molecular mass is the combined mass of all of the atoms or ions contained within a molecule. Molecular mass and formula weight will be used interchangeably. 233.36 amu per 1 molecule of BaSO 4 Help 2 . The molar mass is the mass of exactly one mole of the atoms or molecules that make up a substance. To determine the molar mass you first determine the molecular mass and then change the units to grams per 1 mole of the substance.
Molar mass is numerically the same as the molecular mass.
The only difference is the units. The molecular mass is 233.36 amu per 1 molecule of BaSO 4 . The molar mass is 233.36 grams per 1 mole of BaSO 4 . Calculating Moles from Grams. Moles can be converted to grams by the use of a conversion factor.