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The precipitation of a compound may occur when its concentration exceeds its solubility. This can be due to temperature changes, solvent evaporation, or by mixing solvents. Precipitation occurs more rapidly from a strongly supersaturated solution. The formation of a precipitate can be caused by a chemical reaction.
Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation; their water vapor does not condense sufficiently to precipitate, so fog and mist do not fall.
Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative ...
Assuming a saturated solution at 30 °C, by cooling it to 0 °C (note that this is possible thanks to the freezing-point depression), the precipitation of a mass of sulfate occurs corresponding to the change in solubility from 29% (equilibrium value at 30 °C) to approximately 4.5% (at 0 °C) – actually a larger crystal mass is precipitated ...
Approximately 505,000 km 3 (121,000 cu mi) of water falls as precipitation each year, 398,000 km 3 (95,000 cu mi) of it over the oceans. [10] [15] The rain on land contains 107,000 km 3 (26,000 cu mi) of water per year and a snowing only 1,000 km 3 (240 cu mi). [15] 78% of global precipitation occurs over the ocean. [11]
Unlike hail or sleet, graupel is soft and can be crushed easily in your hand, and is sometimes called "soft hail." It is also usually smaller than hail, with a diameter of around 0.08-0.2 inches.
Ammonium sulfate is an inorganic salt with a high solubility that disassociates into ammonium (NH + 4) and sulfate (SO 2− 4) in aqueous solutions. [1] Ammonium sulfate is especially useful as a precipitant because it is highly soluble, stabilizes protein structure, has a relatively low density, is readily available, and is relatively inexpensive.
The term precipitation is normally reserved for describing a phase change from a colloid dispersion to a solid (precipitate) when it is subjected to a perturbation. [19] Aggregation causes sedimentation or creaming, therefore the colloid is unstable: if either of these processes occur the colloid will no longer be a suspension.