Question

The molecular mass of a compound with an empirical formula of SO, is 128 g/mol. What is the molecular formula?

Answer 1

The empirical formula: SO

Now if we want to get the molecular formula, first, we need to calculate the molar mass of the empirical formula we already have.

The molar mass for SO = 48.0 g/mol

To obtain the molecular formula, we proceed like this:

Divide both molar masses:

The molar mass of the molecular formula/The molar mass of the empirical formula,

128 g/mol/48.0 g/mol = 2.6666 = 3 (approx.)

Now we use this number to multiply our empirical formula. Therefore we have: S3O3

Answer: Molecular formula = S3O3