The concentration of a solution refers to the amount of solute that is dissolved in a given quantity of solvent or solution. It is usually expressed in terms of moles of solute per liter of solution (mol/L), which is also known as molarity (M).
To further elaborate, here is a step-by-step breakdown:
1. Solute: This is the substance that is dissolved in a solvent. In this context, solute examples include substances like sodium thiosulphate ([tex]$Na_2S_2O_3$[/tex]) or hydrochloric acid ([tex]$HCl$[/tex]).
2. Solvent: This is the substance that dissolves the solute. Typically, in many solutions, water is used as the solvent.
3. Solution: When a solute is completely dispersed within a solvent, forming a homogeneous mixture, it is termed a solution.
4. Molarity (M): This is a key concept in concentration measurement, denoted as the number of moles of solute per liter of solution. It is given by the formula:
[tex]\[
\text{Molarity (M)} = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}}
\][/tex]
For example, if you have a [tex]$0.2\ \text{mol/dm}^3$[/tex] solution, it means that there are [tex]$0.2$[/tex] moles of solute (like [tex]$HCl$[/tex] in this case) in every [tex]$1$[/tex] liter (or [tex]$1\ dm^3$[/tex]) of solution.
Ultimately, concentration allows us to quantify and understand the ratio of solute to solvent, making it possible to conduct accurate and reproducible chemical reactions.
