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
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144 g/mol