It is fact that 6.023 × 10 23 formula units of barium nitrate have a mass of 16.6*10^23 ⋅ g . This is what we specify when we say molar mass. And thus the mass of 5.30 × 10 22 formula units of barium nitrate is the quotient multiplied by the molar mass: 5.30 × 10 22 6.023 × 10 23 m o l × 16.6*10^23 ⋅ g ⋅ m o l − 1
