A carbon compound contains 12.8% of carbon, 2.1% of hydrogen and 85.1% of bromine. The molecular weight of the compound is 187.9. What is the molecular formula of the compound? (Atomic weight: H = 1.008, C = 12.0, Br = 79.9)
As always with these problems, it is useful to assume
And we divide thru by the LOWEST molar quantity to give an empirical formula of.....
But we gots a molecular mass, and we know that the molecular formula is a whole number multiple of the empirical formula.
I prefer questions that quote actual microanalytical data.