First, the classification of reagents
According to the purity of chemical reagents, according to the amount of impurities, domestic chemical reagents are divided into four levels:
Primary reagents (premium reagents) are usually indicated by GR.
Secondary reagents (analytically pure reagents) are usually indicated by AR.
Tertiary reagents (chemically pure) are usually indicated by CP.
Level 4 reagents (experimental or industrial reagents) are usually indicated by LR.
In addition, there are some special purity standards for special work purposes. For example, pure spectrum, fluorescent pure, semiconductor pure, and the like. When using, you should use different specifications of reagents according to different experimental requirements. For example, general inorganic experiments can be used with tertiary or quaternary reagents. For analytical experiments, higher purity secondary or even primary reagents are required.
Second, the packaging of reagents
Solid reagents are usually contained in jars with bakelite stoppers. Liquid reagents are contained in jars (or dropper bottles). Light-prone reagents (such as silver nitrate) should be packed in brown bottles. The reagents are labeled to indicate the name, concentration, and purity of the reagent. (In the laboratory, the solids only indicate the name of the reagent, and the liquid must also be labeled with the specified concentration).
Third, the use of reagents
The solid powder reagent can be taken with a clean horn spoon. To take a certain amount of solids, place the solids on paper or on a watch glass and weigh on a scale. For accurate weighing, the weighing bottle is weighed on the balance. The liquid reagent is usually measured by a measuring cylinder. The volume of the measuring cylinder is 5 mL, 10 mL, 50 mL, 500 mL, etc., and the liquid to be measured is injected into the measuring cylinder during use, so that the line of sight and the lowest point of the liquid concave surface in the measuring cylinder are kept horizontal, and then read. The scale on the measuring cylinder is the volume of the liquid. If a small amount of liquid reagent is needed, it can be taken with a dropper. When taking it, care should be taken not to touch or insert the dropper onto or into the wall of the receiving container.
Reagent rule
In order to achieve accurate experimental results, the following rules should be followed when taking reagents to ensure that the reagents are not contaminated and degraded:
1. The reagent cannot be in contact with the hand.
2, to use a clean medicine spoon, measuring cylinder or dropper to take reagents, it is absolutely not allowed to use the same tool while continuously taking a variety of reagents. After taking one reagent, the tool should be washed (the spoon should be dried) before another reagent can be used.
3. After the reagent is taken, be sure to close the stopper. Do not put the wrong bottle cap and the dropper. Do not allow the crown to be worn. After use, put the bottle back to the original place.
4. The removed reagents can no longer be returned to the original reagent bottle.
In addition, the use of reagents should be based on the spirit of saving, as little as possible, so that it is easy to operate and carefully observe the phenomenon, but also get better experimental results.
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