Concentration

In chemistry, concentration is how much of a substance is mixed with another substance.

These glasses containing red dye show changes in concentration. The solutions on the left are more diluted, and the solutions on the right are more concentrated.

The substance that is dissolved (shown as the red dye in the example) is known as the solute. The substance in which the solute is dissolved (shown as the water in the example) is known as the solvent.

To concentrate a solution, one must add more solute, or reduce the amount of solvent. To dilute a solution, one must add more solvent, or reduce the amount of solute.