02
Solutions and pH
Acid, base and solution calculator
Calculate solute mass, a dilution volume, or the ideal pH of a strong acid or base.
m = M × V(L) × molar mass
Solute required2 g
Dissolve the solute and make the solution up to the final volume.
Solution preparation and dilution
Prepare molar solutions and calculate dilution volumes.
Calculate the mass required for a molar solution, the stock volume required for a dilution, or the ideal pH of a strong acid or base at 25 °C.
Mathematical formula
Solution mass and dilution relationships
m = CVMrC1V1 = C2V2
Worked problems
Follow the units through each step.
Prepare 500 mL of 0.100 M NaOH
Problem: How much NaOH (Mᵣ = 40.00 g·mol⁻¹) is required?
- Convert volume: 500 mL = 0.500 L.
- Use m = C × V × Mᵣ.
- Substitute: m = 0.100 mol·L⁻¹ × 0.500 L × 40.00 g·mol⁻¹.
- Dissolve the calculated mass, transfer quantitatively and make up to 500 mL.
Answer: Use 2.00 g NaOH, subject to reagent purity and laboratory procedure.
Dilute 1.00 M stock to 0.100 M
Problem: What stock volume is needed to prepare 500 mL of 0.100 M solution?
- Use C₁V₁ = C₂V₂.
- Rearrange: V₁ = (C₂ × V₂) ÷ C₁.
- Substitute: V₁ = (0.100 × 500 mL) ÷ 1.00.
- Measure the stock and add solvent to a final volume of 500 mL.
Answer: Use 50.0 mL stock solution and dilute to 500 mL total volume.