Schwerlöslichkeit

Schwerlöslichkeit refers to a state where a substance dissolves in a solvent to a very limited extent. This term is primarily used in chemistry and describes a low solubility, meaning only a small amount of the solute can be dispersed in the solvent at a given temperature and pressure. It is a relative term and is often contrasted with terms like "löslich" (soluble), "leichtlöslich" (slightly soluble), and "unlöslich" (insoluble).

The degree of schwerlöslichkeit is quantified by the solubility product, Ksp, for ionic compounds. A low Ksp value indicates that the concentration of dissolved ions in a saturated solution is very low, hence the substance is schwerlöslich. For non-ionic substances, solubility is typically expressed in grams of solute per volume of solvent, and a low value signifies schwerlöslichkeit.

Several factors influence schwerlöslichkeit. Temperature plays a significant role; for most solids, solubility increases with temperature, but for gases, it decreases. The nature of the solute and solvent, following the principle of "like dissolves like," is crucial. Polar solutes tend to dissolve in polar solvents, while nonpolar solutes dissolve in nonpolar solvents. The presence of common ions in the solution can also decrease the solubility of a sparingly soluble salt through the common ion effect.

Understanding schwerlöslichkeit is important in various chemical processes, such as precipitation reactions, the design of pharmaceuticals, and environmental science, where it affects the fate and transport of substances in ecosystems.