Mass to Number of Atoms Conversions

• To go from mass to number of atoms, you must go through the mole.

Mass (g) × (1 mol/atomic mass) × (6.02 × 1023 atoms/1 mole) = # atoms

• Example:
• 45.99 g Na × (1 mol Na/22.99 g) × (6.02 × 1023 Na atoms/1 mole) = 1.204 × 1024 Na atoms

Mole of element

Mass of element (g)

Number of atoms of the element