The measure of the amount of solute dissolved in a solution is referred to as concentration. Concentration can be expressed in various units, such as molarity (moles per liter), mass percent, or parts per million, depending on the context. It provides insights into how much solute is present relative to the solvent, influencing chemical reactions and properties of solutions. Understanding concentration is essential in fields like chemistry, biology, and environmental science, as it affects reaction rates, biological activity, and environmental impacts.