precipitation, in chemistry

precipitation, in chemistry, a process in which a solid is separated from a suspension, sol, or solution. In a suspension such as sand in water the solid spontaneously precipitates (settles out) on standing. In a sol the particles are precipitated by coagulation coagulation (kōăg'y
..... Click the link for more information. . A solute (dissolved substance) may be precipitated from a solution by several means. A solution of salt may be concentrated by evaporation until the salt crystallizes. When a saturated solution of sugar is cooled, sugar crystals form. The addition of a solution of silver nitrate to a solution containing chloride ions results in the formation of insoluble silver chloride: AgNO₃+Cl⁻→NO₃⁻+AgCl↓. In each case the precipitate formed may settle out spontaneously or may be collected by filtration or centrifugation. It is often difficult to obtain a pure substance by a single precipitation, and a substance may be further purified by reprecipitation after it has been redissolved. The term precipitation is also applied to the separation of particles of a solid or liquid suspended in a gas.

precipitation, in meteorology

precipitation, in meteorology, condensed moisture that falls to the surface of the earth in the form of rain rain, precipitation in liquid form. It consists of drops of water falling from clouds; if the drops are very small, they are collectively termed drizzle. Rain plays a key role in the hydrologic, or water, cycle in which moisture from the oceans evaporates, condenses
..... Click the link for more information. , sleet sleet, precipitation of small, partially melted grains of ice. As raindrops fall from clouds, they pass through layers of air at different temperatures. If they pass through a layer with a temperature below the freezing point, they turn into sleet.
..... Click the link for more information. , snow snow, precipitation formed by the sublimation of water vapor into solid crystals at temperatures below freezing. Sublimation resulting in the formation of snow takes place about a dust particle, as in the formation of raindrops.
..... Click the link for more information. , hail hail, precipitation in the form of pellets composed of ice or of ice and snow, occurring at any time of the year, usually during the passage of a cold front or during a thunderstorm. Small hailstones have a soft center and a single outer coat of ice.
..... Click the link for more information. , frost frost or hoarfrost, ice formed by the condensation of atmospheric water vapor on a surface when the temperature of the surface is below 32°F; (0°C;). In the formation of frost, a gas (water vapor) is changed directly to a solid (see dew ).
..... Click the link for more information. , or dew dew, thin film of water that has condensed on the surface of objects near the ground. Dew forms when radiational cooling of these objects during the nighttime hours also cools the shallow layer of overlying air in contact with them, causing the condensation of some
..... Click the link for more information. .

precipitation

All liquid and solid water particles that fall from clouds and reach the ground, including drizzle, rain, snow, ice crystals, and hail. The essential difference between a precipitation particle and a cloud particle is size; an average raindrop has a mass equivalent to that of about one million cloud droplets. Precipitation elements (ice crystals or droplets that form around soluble particles such as salt) form directly from the vapour state and get larger through collision and coalescence. Eventually they become large enough to respond to gravity, and they fall to the ground.

precipitation (redirected from downfall)

precipitation, in chemistry

precipitation, in meteorology

precipitation

precipitation
(redirected from downfall)