For example, hexane has a molecular formula of C
14 , or structurally CH
3 , implying that it has a chain structure of 6 carbon atoms, and 14 hydrogen atoms. However, the empirical formula for hexane is C
7 . Likewise the empirical formula for hydrogen peroxide , H
2 , is simply HO expressing the 1:1 ratio of component elements. Formaldehyde and acetic acid have the same empirical formula, CH
2 O . This is the actual chemical formula for formaldehyde, but acetic acid has double the number of atoms.