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An evaporating dish is a piece of laboratory glassware used for the evaporation of solutions and supernatant liquids, [a] and sometimes to their melting point.Evaporating dishes are used to evaporate excess solvents – most commonly water – to produce a concentrated solution or a solid precipitate of the dissolved substance.
Wollaston's diagram of a cryophorus. When the empty ball on the right is immersed in a freezing mixture of snow and salt, the water in the ball on the left freezes in a few minutes. A cryophorus is a glass container containing liquid water and water vapor. It is used in physics courses to demonstrate rapid freezing by evaporation. A typical ...
Evaporation is an essential part of the water cycle. The sun (solar energy) drives evaporation of water from oceans, lakes, moisture in the soil, and other sources of water. In hydrology, evaporation and transpiration (which involves evaporation within plant stomata) are collectively termed evapotranspiration. Evaporation of water occurs when ...
If water is cooled at a rate on the order of 10 6 K/s, the crystal nucleation can be avoided and water becomes a glass—that is, an amorphous (non-crystalline) solid. Its glass transition temperature is much colder and harder to determine, but studies estimate it at about 136 K (−137 °C; −215 °F). [ 9 ]
This equipment can be used in cases other than simple removal of water. One example is the esterification of butanol with acetic acid catalyzed by sulfuric acid. The vapor contains 63% ester, 29% water and 8% alcohol at reflux temperature and the organic layer in the trap contains 86% ester, 11% alcohol and 3% water which is reintroduced.
A watch glass is a circular concave piece of glass used in chemistry as a surface to evaporate a liquid, to hold solids while being weighed, for heating a small amount of substance, and as a cover for a beaker. When used to cover beakers, the purpose is generally to prevent dust or other particles from entering the beaker; the watch glass does ...
A wash bottle is a squeeze bottle with a nozzle, used to rinse various pieces of laboratory glassware, such as test tubes and round bottom flasks. Wash bottles are sealed with a screw-top lid. When hand pressure is applied to the bottle, the liquid inside becomes pressurized and is forced out of the nozzle into a narrow stream of liquid.
A rotary evaporator [1] (rotovap) is a device used in chemical laboratories for the efficient and gentle removal of solvents from samples by evaporation.When referenced in the chemistry research literature, description of the use of this technique and equipment may include the phrase "rotary evaporator", though use is often rather signaled by other language (e.g., "the sample was evaporated ...