[China Glass Net] Glass evaporating dish is complete in specifications, mainly used for evaporation, concentration and crystallization of liquids. It can withstand high temperature, but it can't be quenched. When the amount of liquid is too much, it can be heated and evaporated directly on the flame. When the amount of liquid is small or viscous, it should be heated through an asbestos web. The evaporating dish is mainly used for distillation and other operations and is an ideal chemical distillation instrument.
The glass evaporating dish can withstand high temperature, but it can not be quenched. The evaporating dish should be taken and removed with a pliers. When heating, fix it with a tripod or iron frame. When the amount of liquid is large, it can be heated and evaporated directly on the flame, but the amount of liquid cannot exceed two-thirds of its volume. When the amount of liquid is small or viscous, it should be heated through an asbestos web. The evaporating dish is mainly used for distillation and other operations and is an ideal chemical distillation instrument.
When it is desired to obtain a solid from a solution, it is often necessary to remove the solvent by heating, in which case a glass evaporating dish is used. The faster the solvent evaporates, the smaller its crystalline particles. Depending on the desired evaporation rate, it is possible to use the rapid evaporation of the evaporating dish on the flame, the gentle evaporation of the water bath, or the evaporation of the solution at room temperature. Generally, when solids are to be purified in a laboratory, the purity of the solids is increased by recrystallization. The method of recrystallization is usually carried out by selecting an appropriate solvent to make impurities in the impurities have poor solubility or insoluble characteristics in the solvent, and the component to be purified has a relatively good solubility in the solvent. The solid to be purified is first dissolved in a small amount of hot solvent. If there is insoluble impurities, the solution should be filtered immediately under such warm conditions; thus, the insoluble solid impurities can be left in the filter paper by filtration. The purity of the main component in the filtrate under filtration can be increased, and the filtrate is poured into an evaporating dish to crystallize it, and the obtained crystal is a substance having an increased purity. Water bath heating is a mode of indirect heating. When the heated material is easily decomposed when exposed to high temperatures or crystallized to obtain larger particles, it can be heated in a water bath. When heating in a water bath, if a chemical reaction is carried out using a flask, an appropriate amount of water may be placed in the large beaker, placed on a Bunsen burner, and the reaction flask may be placed in hot water in a beaker. When recrystallizing from an evaporating dish, a beaker having a cup opening slightly smaller than the diameter of the evaporating dish can be used, and the water is allowed to reach a height of about two-thirds, and the evaporating dish is placed over the cup; when the water is heated to boiling, The evaporating dish can be heated by boiling steam.
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