Mole concept

Science

Definition

The mole is the SI unit for measuring the amount of a substance. One mole contains exactly 6.022 × 10²³ particles (Avogadro's number) and equals the substance's molar mass in grams. It bridges the gap between the atomic scale and measurable laboratory quantities.

Examples

  • One mole of carbon-12 has a mass of exactly 12 grams
  • One mole of water (18.02 g) contains 6.022 × 10²³ water molecules
  • Using moles to convert between grams and number of atoms in a sample
Key Fact

1 mole = 6.022 × 10²³ particles (Avogadro's number).

Related Terms

Stoichiometry Molar ratios Concentration Balancing equations

Study This Concept

Practice mole concept with free review games in these units:

Chemistry Unit 5: Stoichiometry