Dilution of solutions

1. What is Dilution?

Dilution is the process of reducing the concentration of a solution by adding distilled water.
The amount of solute remains the same, but the volume of solution increases, decreasing the concentration.

$C_1V_1 = C_2V_2$

where:

infoNote

Problem:

A $0.20$ $mol·dm⁻³$ solution is diluted by adding $250$ $cm³$ of distilled water to $150$ $cm³$ of the solution.

Calculate the final concentration of the diluted solution.

Solution:

$C_2 = \frac{C_1V_1}{V_2}$

$C_2 = \frac{(0.20)(0.15)}{0.4}$

$C_2 = 0.075 mol·dm⁻³$

Thus, the final concentration of the diluted solution is $0.075$ $mol·dm⁻³$ .

✅ Dilution does NOT change the number of moles of solute, only the concentration.

✅ The greater the volume of water added, the lower the final concentration.

✅ Always convert $cm³$ to $dm³$ ( $1000$ $cm³$ $=$ $1$ $dm³$ ) when using the formula.