precipitadas

Precipitadas is a term used in Portuguese to refer to substances that have formed a solid phase and separated from a liquid during a chemical process. In chemistry, the solid produced in such a process is called a precipitado (with its feminine form precipitada for agreement with feminine nouns), and the phenomenon is known as precipitação. Precipitated substances arise when the solubility of a compound is exceeded or when a reaction creates a product with low solubility in the solvent.

The formation of precipitated solids involves concepts such as solubility, saturation, and nucleation. A solution becomes supersaturated when it contains more dissolved material than it can hold at a given temperature. Nucleation provides the initial sites for crystal growth, after which particles grow and aggregate to form a visible solid. Precipitation can be homogeneous (reactions occurring entirely in the liquid) or heterogeneous (involving solid surfaces that facilitate nucleation).

Isolating precipitated solids typically involves filtration, decantation, or centrifugation, followed by drying to obtain a stable solid. The properties of precipitated substances depend on their composition and the conditions of formation; they can vary in size, shape, color, and purity.

Applications are wide, including water treatment (removal of metal ions as insoluble hydroxides or carbonates), purification of compounds, and qualitative/quantitative chemical analyses through characteristic precipitate tests. Common examples of precipitated solids include silver chloride (AgCl), barium sulfate (BaSO4), calcium carbonate (CaCO3), and iron hydroxide (Fe(OH)3).

See also: precipitation, solubility, nucleation, filtration.