Dilution Equation
Relates concentration and volume before and after dilution.
Formula
Variables
Example
Dilute 2M to 0.5M: quadruple the volume
How it works
This equation says that when you add only solvent to a solution, the amount of dissolved substance stays the same even though the concentration changes. Since concentration is amount per unit volume, making the volume larger lowers the concentration in a predictable way. So the product of concentration and volume stays constant before and after dilution, as long as no solute is added or lost.
When to use it
Use this when you need to find how concentrated a solution becomes after adding water or another solvent. It is common in lab work, water-quality testing, chemistry prep, and any situation where a stock solution is diluted to a new target concentration.
Worked example, step by step
A researcher has 40 mL of a 3 M salt solution and wants to dilute it to 1.5 M. Use C1V1 = C2V2 (3 M)(40 mL) = (1.5 M)(V2) 120 = 1.5V2 V2 = 120 / 1.5 V2 = 80 mL Final answer: the diluted solution must have a total volume of 80 mL. Water to add = 80 mL - 40 mL = 40 mL
Common mistakes to avoid
- Using the added solvent volume instead of the final total volume in V2
- Mixing up which concentration is the starting value and which is the final value
- Forgetting that concentration and volume units must match on both sides of the equation
Did You Know?
The core equation for preparing solutions.
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