molar mass over grams of element

The above answer is somewhat correct. In order to find the molecular formula when given the empirical formula, you must first find the molar mass of the empirical formula.

MOLAR MASS

# atoms element A x atomic mass element A (periodic table) = mass A

# atoms element B x atomic mass element B (periodic table) = mass B

... etc.

Add up all of the mass values found above and you have the molar mass.

Then, after you have found the empirical formula's molar mass, you divide the molar mass of the molecular formula by the empirical formula's molar mass (solving for n).

MOLECULAR FORMULA EQUATION: N (Empirical formula) (read as N times empirical formula) where:

N = Molar mass substance

---- Molar Mass emp. form.