What is the Difference Between Empirical and Molecular Formulas?

The main difference between empirical and molecular formulas lies in the ratio of atoms in a compound. Here is a comparison of the two types of formulas:

Empirical Formula:

• Represents the simplest whole-number ratio of atoms in a compound.
• Found from mass percentages of elements in a compound.
• Used to determine the actual elemental composition of a compound.
• Can be found through combustion or composition analysis.

Molecular Formula:

• Shows the actual number of each type of atom in a molecule.
• Found using the empirical formula and the molecular weight of the compound.
• Represents the actual elemental composition of a compound.
• The molecular formula is a multiple of the empirical formula, although sometimes the empirical formula is multiplied by "1", making the two formulas the same.

For example, the empirical formula for glucose is CH₂O, while its molecular formula is C₆H₁₂O₆. The molecular formula is a multiple of the empirical formula, which is simplified to represent the simplest whole-number ratio of the elements in the compound.

Comparative Table: Empirical vs Molecular Formulas

Here is a table comparing the differences between empirical and molecular formulas:

For example, consider the compound glucose. It has a molecular formula of C6H12O6 and an empirical formula of CH2O. The molecular formula shows the actual number of atoms of each element present in a molecule, while the empirical formula represents the simplest whole-number ratio of atoms.