Question

How can you calculate empirical formulas?

Answer 1

The empirical formula is the simplest whole number ratio that defines constituent atoms in a species.

Explanation:

See here and here, and here for an example.

The standard procedure for calculation is to get the elemental percentages, which must add up to 100% (why?), and then assume a `100*g` mass, and the divide thru the elements by the atomic mass of each element. When these are normalized you get an empirical formula, which may or may not be the molecular formula.