However, their molecular formulas, which express the number of atoms in each molecule of a chemical compound, are not the same.
It is standard for many ionic compounds, like calcium chloride (CaCl2), and for macromolecules, such as silicon dioxide (SiO2).
The molecular formula, on the other hand, shows the number of each type of atom in a molecule.
However, chemists were not able to determine the exact amounts of these elements and were only able to know their ratios, hence the name "empirical formula".
[3] A chemical analysis of a sample of methyl acetate provides the following elemental data: 48.64% carbon (C), 8.16% hydrogen (H), and 43.20% oxygen (O).