Dilution and Concentration Calculations
Start with the big picture
Concentration may be expressed as a percentage, ratio strength, ppm, or molar and equivalent-based units. Percentage expressions distinguish the mass or volume of solute from the total mixture or solution; for solutions, w/v is assumed when the basis is not specified. Ratio strength can be related to percentage, while ppm describes very dilute aqueous concentrations. For dilution, C₁V₁ = C₂V₂ applies when units are consistent; mixing solutions uses a mass-balance relationship, and serial dilution requires tracking successive dilution factors. The lesson also introduces alligation for combining two strengths and approaches to isotonic preparations. Further calculations address specific gravity, alcohol proof, displacement by solids, weight-based dilution, stock solutions, and geometric dilution when minimum weighable quantity is a concern.
What you'll learn
- Distinguish common concentration expressions, including percentage, ratio strength, ppm, and molar units.
- Apply the dilution equation and mass balance to solution preparation and mixing.
- Explain how alligation relates two strengths to a desired intermediate concentration.
- Identify calculation considerations for isotonic solutions, specific gravity, and displacement value.
- Describe the role of stock solutions and geometric dilution in weighing potent powders.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
