Chemical Solution Mixer
Calculate how to dilute a stock solution using C₁V₁ = C₂V₂.
Enter any three values to find the fourth — for chemistry labs, cleaning products, and medical prep.
Molarity is the most commonly used measure of solution concentration in chemistry. It expresses how many moles of solute are dissolved per liter of solution — giving a precise, temperature-independent way to describe how “strong” a solution is.
Molarity formula: M = n ÷ V
Where:
- M: molarity (mol/L, also written as “M”)
- n: moles of solute
- V: volume of solution in liters (not volume of solvent, the total solution volume)
Moles from mass: n = mass (g) ÷ molar mass (g/mol)
Molar mass is the sum of atomic masses of all atoms in one molecule (found on the periodic table).
Dilution formula (when diluting a stock solution): M₁ × V₁ = M₂ × V₂
- M₁: concentration of stock solution
- V₁: volume of stock solution to take
- M₂: desired final concentration
- V₂: desired final volume
Other concentration units for reference:
- Molality (m): mol solute per kg of solvent (not solution), temperature-independent
- Mass percent (% w/w): (mass of solute ÷ total mass of solution) × 100
- Parts per million (ppm): mg of solute per liter of solution (for very dilute solutions)
- Normality (N): moles of equivalents per liter, used in acid-base and redox titrations
Worked example — preparing NaCl solution: You want 500 mL of 0.5 M sodium chloride (NaCl) solution.
- Molar mass of NaCl: Na (22.99) + Cl (35.45) = 58.44 g/mol
- Moles needed: 0.5 M × 0.500 L = 0.25 mol
- Mass to weigh: 0.25 × 58.44 = 14.61 grams of NaCl
- Procedure: Dissolve 14.61 g NaCl in ~400 mL distilled water, then add water to reach exactly 500 mL.
Dilution example: You have 2 M HCl stock solution and need 250 mL of 0.1 M HCl.
- M₁V₁ = M₂V₂ → 2 × V₁ = 0.1 × 250
- V₁ = 12.5 mL of stock solution
- Add 12.5 mL of 2 M HCl to a 250 mL volumetric flask, then fill to the 250 mL mark with distilled water.
Safety note: Always add acid to water — never water to concentrated acid.