solutesmolecules

Solute molecules are the substances dissolved in a solvent to form a solution. They can be molecular species that remain intact, such as glucose, or ions resulting from the dissociation of salts like sodium chloride. The term solute is contrasted with the solvent, which is present in the greater amount and largely determines the solution's bulk properties.

Solubility describes how much solute can be dissolved in a given solvent at a specified temperature. Concentrations are expressed in molarity, molality, or mole fraction. Dissolution often occurs at the surface of a solid or at interfaces, and the rate is influenced by temperature, agitation, particle size, and solvent structure. For gases, dissolution depends on pressure and follows Henry's law; for most solids, solubility tends to increase with temperature in liquids.

Solute molecules affect solution properties through colligative effects, including boiling-point elevation, freezing-point depression, and osmotic pressure. Electrolytes contribute additional particles, altering these properties compared with nonelectrolyte solutes.

Applications of solute chemistry include preparation of pharmaceutical formulations, chemical analysis, and biological systems, where solute concentrations govern osmoregulation and nutrient transport. In biochemistry, the osmolarity of cellular fluids depends on the total concentration of dissolved particles, including solute molecules and ions.