Question

What is meant by the concentration of a solution? Explain by giving an example.

Answer 1

The concentration of a solution Is the amount of solute present in a given amount of solution or solvent. This can be mathematically written as:
The concentration of solution $=\frac{\text{Amount of solute}}{Amountofsolution}$
Or
The concentration of solution $=\frac{\text{Amount of solute}}{\text{Amount of solvent}}$
Mainly one expresses concentration in 2 ways:
(a) Mass by mass percentage:
Mass of solute Mass by mass percentage of a solution $=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 100$
(b) Mass by volume percentage:
Mass of solute Mass by volume percentage of a solution $=\frac{\text{Mass of solute}}{\text{Volume of solution}}\times 100$
Eg: Consider $30g$ of sugar (solute) dissolved in $150g$ of water (solvent).
Then the mass of solute $=30g$
Mass of solvent $=150g$
Mass of solution $=$ Mass of solute • mass of solvent
$=30+150$
$=180g$
Therefore. the concentration of solute expressed using mass by mass percentage is:
Mass by mass percentage of solution $=$ (Mass of solute/Mass of solution) $\times 100$
$=\left(\frac{30}{180}\right)\times 100$
$=\left(\frac{1}{6}\right)\times 100$
$=16.6\%$