molecular weight is 284.5 g/mol what is the molecular formula.76.0% C, 12.8% H, 11,2%O.

Answer 1

Take a 100 g sample. That gives you
76.0g C
12.8 g H
11.2 g O

Convert to mols. mol = grams/atomic mass.
Then find the ratio; the easy way to do that is to divide the smallest number by itself then divide all of the other numbers by the same small number. That will give you the empirical formula. Now you need an empirical formula mass.
(284.5/empirical formula) = n. Round n to a whole number and the molar formula is (empirical formula)_n
Post your work if you get stuck.