What would you use to convert the empirical formula of a compound to a molecular formula?
You need the molar mass or molecular mass of a compound to convert its empirical formula to a molecular formula.
For example, assume you know that the empirical formula of a compound is CH₂O.
To determine its molecular formula, you have to do an experiment to find its molecular (molar) mass.
The empirical formula is the simplest formula of a compound. The actual formula is an integral multiple of the empirical formula.
Let's assume that the molecular mass turned out to be about 180 u.
If the empirical formula is CH₂O, the actual formula is
The empirical formula mass of CH₂O is 30.03 u. The molecular mass of 180 u must be some multiple of this number.
∴ The molecular formula =
Hope this helps.