The molecular formula of valproic acid is C8H16O2. The molar mass of a substance is the sum of the atomic mass of the elements involved in a compound. For valproic acid, we calculate the molar mass as follows:
C = 8 x 12 g/mol H = 1 x 16 g/mol O = 2 x 16 g/mol ---------------------- 144 g/mol
