Hydrogen peroxide has the empirical formula HO and an empirical formula weight of 17.0 amu. If the molecular weight is 34.0 amu, what is the molecular formula?
First, you want to find the ratio between the empirical formula and molecular formula; that is, how much has the molecular formula been simplified to reach the empirical formula. We do this by dividing the molecular weight by the empirical weight.
Therefore, the molecular formula has been halved in order to obtain the empirical formula. Now multiple the empirical formula by 2 to obtain the molecular formula.
HO x 2 =