Avogadro’s number, approximately 6.022 × 10²³, represents the number of particles—such as atoms, molecules, or ions—contained in one mole of a substance. Just as a dozen means 12 items, a mole means 6.022 × 10²³ entities.
This concept allows chemists to count extremely small particles like atoms and molecules in measurable amounts. For example:
- 1 mole of carbon atoms = 6.022 × 10²³ carbon atoms
- 1 mole of water molecules = 6.022 × 10²³ H₂O molecules
Avogadro’s number links the microscopic world (individual particles) to the macroscopic world (grams and liters), making it essential for performing calculations in chemical reactions, stoichiometry, gas laws, and molar mass conversions. It forms the foundation of quantitative chemistry.