Empirical formula

Definition

An empirical formula represents the simplest whole-number ratio of elements in a compound. It does not show the actual number of atoms, but rather the relative proportions.

5 Must Know Facts For Your Next Test

1. Empirical formulas are derived from experimental data.
2. They can be identical to molecular formulas if the molecule's composition is already in the simplest ratio.
3. The empirical formula for glucose (C6H12O6) is CH2O.
4. To determine an empirical formula, convert mass percentages to moles and then simplify the ratios.
5. Empirical formulas are essential for understanding stoichiometry in chemical reactions.

Review Questions

• What is an empirical formula and how does it differ from a molecular formula?
• How do you determine the empirical formula from mass percent composition?
• Why might two different compounds have the same empirical formula?

Related terms

Molecular Formula:

Shows the exact number of atoms of each element in a molecule.

Stoichiometry:

The calculation of reactants and products in chemical reactions based on balanced equations.

% Composition: % Composition indicates the percentage by mass of each element in a compound.