Molar and molecular weight of H2O

• Relative molecular weight of H2O: 18.01528
• Molar mass of H2O: 18.01528 g/mol (0.01802 kg/mol)

Calculation of the relative molecular and molar mass of H2O

• Mr[H2O] = Ar[H] * 2 + Ar[O] = 1.00794 * 2 + 15.9994 = 18.01528
• Molar mass (kg/mol) = Mr[H2O] : 1000 = 18.01528 : 1000 = 0.01802 kg/mol

H2O: percent composition by element

• Hydrogen (H) = 2.01588 : 18.01528 * 100 = 11.19 %
• Oxygen (O) = 15.9994 : 18.01528 * 100 = 88.81 %

Molar mass calculator