• SI unit of amount of substance
  • one mole contains exactly 6.02214076e23 entities (Avogadro’s number)
  • bridges the atomic and macroscopic scales: one mole of carbon-12 has a mass of exactly 12 grams
  • enables stoichiometry: balanced equations give mole ratios of reactants and products
  • molar mass (g/mol) equals the atomic or molecular mass expressed in daltons
  • molar volume of an ideal gas at STP: 22.4 liters
  • molarity (mol/L) is the standard concentration unit in solution chemistry
  • named by Wilhelm Ostwald, derived from the German Molekul