ChemixaLEARN CHEMISTRY

Molarity (M)

Quantity: amount concentration · Category: Concentration

Molarity is the amount concentration of a solute in a solution, defined as moles of solute per liter of solution. It is the most widely used concentration unit in chemistry. Molarity is temperature-dependent because a solution's volume changes with temperature: a solution prepared as 1.000 M at 25 °C will have a slightly different molarity at another temperature. Always written with a capital M, e.g. 0.100 M NaCl.

Relation to SI

1 M = 1 mol/L = 1000 mol/m³

Examples

  • Dissolving 1 mol of NaCl and diluting to exactly 1.00 L of solution gives a 1.00 M solution
  • Dilution: C₁V₁ = C₂V₂, e.g. 100 mL of 1.0 M diluted to 1.0 L gives 0.10 M
  • Titrations report acid and base concentrations in mol/L (M)