Concentration units are measurements that express the amount of a substance in a given volume of solution. Common units include molarity (moles of solute per liter of solution), molality (moles of solute per kilogram of solvent), and percent concentration (mass or volume of solute per total mass or volume of solution). These units help scientists and researchers understand how much of a substance is present in a mixture. Different concentration units are used depending on the context and the properties of the substances involved. For example, molarity is often used in chemical reactions, while percent concentration is common in food and beverage industries. Understanding these units is essential for accurate measurements and effective communication in scientific fields.