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Alternatively, a beaker may be covered with another larger beaker that has been inverted, though a watch glass is preferable. Beakers are often graduated, that is, marked on the side with lines indicating the volume contained. For instance, a 250 mL beaker might be marked with lines to indicate 50, 100, 150, 200, and 250 mL of volume.
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 ...
With a laboratory scale, the tare weight is the mass of the flask and the net weight is the mass of the contents. This can be useful in computing the cost of the goods carried for purposes of taxation or for tolls related to barge, rail, road, or other traffic, especially where the toll will vary with the value of the goods carried (e.g., tolls on the Erie Canal).
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.
Beaker (glassware) Many of these flasks can be wrapped in a protective outer layer of glass, leaving a gap between the inner and outer walls. These are called jacketed flasks; they are often used in a reaction using a cooling fluid.
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
It differs from the beaker in its tapered body and narrow neck. [4] Depending on the application, they may be constructed from glass or plastic, [5] in a wide range of volumes. [6] The mouth of the Erlenmeyer flask may have a beaded lip that can be stoppered or covered.
Flat-bottomed flask: A flask with similar uses as the round-bottom flask, but with a flat bottom that allows it to stand on a level surface.; Florence flask: A flask similar to the flat-bottomed flask that has round bodies and either a round bottom or a flat bottom so that one can stand the flask on a level surface.