🧪 Molarity Calculator

Molarity (M) is the number of moles of solute dissolved per litre of solution: M = n ÷ V. It is the most common way to express solution concentration.

NaCl molar mass = 58.44 g/mol. Moles = 5.85 ÷ 58.44 = 0.1001 mol. Molarity = 0.1001 ÷ 0.5 L = 0.200 mol/L (0.2 M).

Molarity (M) = moles per litre of solution. Molality (m) = moles per kilogram of solvent. Molality is temperature-independent; molarity is not.

Weigh out 1 mole of solute (mass = molar mass in grams), dissolve it in solvent, and transfer to a 1-litre volumetric flask. Fill to the 1-litre mark with solvent.

Normality (N) = Molarity × number of equivalents (n-factor). For HCl, n=1 so 1 M = 1 N. For H₂SO₄, n=2 so 1 M = 2 N.

Temperature changes the volume of the solution, which changes molarity. A solution heated up becomes less concentrated as the volume expands.