solutes

Solutes are substances dissolved in a solvent to form a solution. The solvent is the component present in the greater amount. Solutes may be solids, liquids, or gases and, in aqueous solutions, often exist as ions or molecules dispersed uniformly.

Concentration describes how much solute is present relative to the solvent or solution. Common measures include molarity, molality, mole fraction, mass percentage, and parts per million. Solubility is the maximum amount of solute that can dissolve at a given temperature and pressure; a saturated solution contains this amount, while supersaturated solutions temporarily hold more.

Solutes can be electrolytes, which dissociate into ions and increase electrical conductivity, or non-electrolytes, which do not. The behavior of solutes is influenced by temperature, pressure, and the solvent’s nature; for gases, solubility generally decreases with temperature and increases with pressure.

Colligative properties depend on the number of dissolved particles rather than their identities. They include boiling-point elevation, freezing-point depression, osmotic pressure, and vapor-pressure lowering. The concept is widely used in chemistry and biology, for example in osmoregulation and food science.

In ideal solutions, Raoult’s law provides a simple relation between vapor pressure and solvent concentration, though real solutions show deviations due to solute–solvent interactions. Common solutes include table salt (NaCl) in water, sugars like glucose in water, and ethanol in water.