solutés

Solutés (solutes) are substances that are dissolved in a solvent to form a solution. In any solution, the solvent is typically the component present in greater quantity, while the solute is present in smaller amounts. Solutes can be solids, liquids, or gases. Common examples include table salt dissolving in water, sugar in water, and carbon dioxide dissolved in water under pressure.

Solubility describes how much solute can dissolve at a given temperature and pressure. A solution may be unsaturated (can dissolve more solute), saturated (cannot dissolve more at that conditions), or supersaturated (unstable, containing more solute than normally possible). Concentration quantifies how much solute is present, with molarity (moles per liter) as a common measure; other metrics include mass fraction, mole fraction, and percent by mass.

When solutes dissociate or react in solution, they form ions or new species, affecting properties such as electrical conductivity and reactivity. The solubility of a substance is influenced by interactions between solute and solvent, temperature, and, for gases, pressure.

For solids, solubility generally increases with temperature; for gases, solubility often decreases with rising temperature and increases with higher pressure (Henry's law). The concept of solubility is central to chemistry, biology, environmental science, and pharmaceuticals, where it governs nutrient transport, drug formulation, precipitation, and crystallization processes.