Molar and molecular weight of SO3

• Molecular formula: SO3 or O3S
• Relative molecular weight of SO3: 80.0632
• Molar mass of SO3: 80.0632 g/mol (0.08006 kg/mol)

Calculation of the relative molecular and molar mass of SO3

• Mr[SO3] = Ar[O] * 3 + Ar[S] = 15.9994 * 3 + 32.065 = 80.0632
• Molar mass (kg/mol) = Mr[SO3] : 1000 = 80.0632 : 1000 = 0.08006 kg/mol

SO3: percent composition by element

• Oxygen (O) = 47.9982 : 80.0632 * 100 = 59.95 %
• Sulfur (S) = 32.065 : 80.0632 * 100 = 40.05 %

Molar mass calculator