What is the empirical formula of C6H18O3?

CH3O

C2H5O

C2H6O

C2H5O5

The answer is: C2H6O.

Molecular formula is chemical formula that shows the total number and kinds of atoms in a molecule, but not their structural arrangement (in this example C6H18O).

Molecular formula shows that compound has six carbon, eighteen hydrogen and three oxygen atoms.

Empirical formula gives the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms.

Proportion of atoms: C : H : O = 2 : 6 : 1.

In this example, molecular formula is divided by three.