Beginner Topic 300 of 1102 States of Matter & Solutions
Dilution
Adding solvent to lower concentration, using M1V1 equals M2V2.
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In-depth explanation of Dilution
Dilution is the process of reducing the concentration of a solution by adding solvent, while the amount of solute stays the same. Because the moles of solute are unchanged, the relation M1V1 = M2V2 applies, where M1 and V1 are the initial molarity and volume and M2 and V2 are the final values. The dilution factor is V2/V1, which equals the ratio of the initial to the final concentration. When diluting a concentrated acid, the acid should always be added slowly to water, never the reverse, because mixing releases a large amount of heat. Careful dilution is an essential laboratory skill.
Going deeper: Dilution
Key ideas: Check with the dilution factor: M2 = M1 V1/V2. For serial dilutions multiply factors, e.g. three 1:10 steps give 1:1000. Use a pipette for the aliquot and volumetric flask to the mark, adding water to the final volume, not adding a fixed volume of water. Units of V cancel, so keep both the same.
Common mistakes and connections: Students add the stated volume of solvent to the aliquot, so the final volume differs from the required one. Another error is using the equation when reacting species are consumed; it applies only to dilution. Mixing two solutions of different concentrations needs total moles over total volume instead. Links to molarity, titration and dosing in medicine.
Visualization of Dilution
Dilution: M1V1 = M2V2, because moles of solute stay constant while the volume grows; 0.1 L of 12 M acid made up to 1 L gives 1.2 M. The interactive lesson shows this as a live animation or chart.
Worked example and use case
To prepare 500 mL of 0.1 M solution from a 2.0 M stock, take 25 mL of stock and dilute it to 500 mL, since 2.0 × 25 = 0.1 × 500.
Frequently asked questions about Dilution
What is Dilution?
Adding solvent to lower concentration, using M1V1 equals M2V2.
Is Dilution a beginner, intermediate or advanced topic?
Dilution is a beginner topic in States of Matter & Solutions. It needs no earlier chemistry lessons and is a good starting point.
What should I learn before Dilution?
Study these earlier topics in States of Matter & Solutions first: Mass Percent, Parts Per Million, Normality.
What comes after Dilution?
The next topics in States of Matter & Solutions are Henry's Law and Temperature and Solubility.
Can I practise Dilution with quizzes?
Yes. The interactive lesson includes a self-check question on Dilution, and the States of Matter & Solutions quiz draws on every topic in this area.
Where Dilution fits in States of Matter & Solutions
Dilution is topic 81 of 109 in States of Matter & Solutions.