Molecular mass:

Molecular mass is the sum of atomic masses of all the atoms present in the molecule.

Examples:

(i) Molecular mass of water (H₂O):

Molecular mass of water H₂O = 2 (atomic mass of H) + atomic mass of oxygen

= 2(1.006) + 16.00

= 2.016 +16.00 = 18.016 amu

(ii) Molecular mass of Sulphuric acid (H₂SO₄):

Molecular mass of H₂SO₄ = (2) + (1 x 32) + (4 x 16) = 98 amu