Molar and molecular weight of SeO3

• Molecular formula: SeO3 or O3Se
• Relative molecular weight of SeO3: 126.9582
• Molar mass of SeO3: 126.9582 g/mol (0.12696 kg/mol)

Calculation of the relative molecular and molar mass of SeO3

• Mr[SeO3] = Ar[O] * 3 + Ar[Se] = 15.9994 * 3 + 78.96 = 126.9582
• Molar mass (kg/mol) = Mr[SeO3] : 1000 = 126.9582 : 1000 = 0.12696 kg/mol

SeO3: percent composition by element

• Oxygen (O) = 47.9982 : 126.9582 * 100 = 37.806 %
• Selenium (Se) = 78.96 : 126.9582 * 100 = 62.194 %

Molar mass calculator