Question: how to calculate empirical formula given molar mass?
Answer: Empirical formula weight = (1 x 12.01g/mol) + (2 x 1.01g/mol) + (1 x 16.00g/mol) = 30.02g/mol. Divide the molar mass for the molecular formula by the empirical formula mass. The result determines how many times to multiply the subscripts in the empirical formula to get the molecular formula.