An unknown sample with a molecular mass of 180.0g is analyzed to yield 40% C, 6.7% H, and 53.3% O. What is the empirical formula and the molecular formula of this compound?

Answer 1

Take a 100 g sample which will give you
40 g C
6.7 g H
53.3 g O.
Convert to mols.
40/12 = ? mols C.
6.7/1 = ? mols H
53.3/16 = ? mols O

Now find the ratio of the elements t each other with the smallest being 1.00. The easy way to do that is to divide the smallest number by itself (which makes it 1.00), then divide the other two numbers by the same small number. That will give you the empirical formula.

To find the molecular formula, do this
empirical formula mass = ?(add the atomic masses) and substitute into
empirical formula x n = molar mass, solve for n and the molecular formula is (CxHyOz)_n

Answer 2

14