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What issues should be paid attention to about the use of chemical reagents
Chemical reagents have always been hailed as the "eyes of science" and "the ruler of quality". They are not only essential material conditions for scientific research and analysis, but also essential materials for exploring the unknown world and developing new technologies. Chemical reagents are the most diverse, most frequently consumed, and most dangerous substances in the laboratory. If used improperly, they will cause harm to laboratory personnel and laboratory equipment. So let's teach you how to use chemical reagents correctly.
Access to chemical reagents
The solid powder reagent can be taken with a clean horn spoon. To take a certain amount of solids, put the solids on paper or watch glass and weigh them on a platform scale. For accurate weighing, use a weighing bottle to weigh on the balance. Liquid reagents are usually measured in graduated cylinders. The capacities of the graduated cylinders are: 5 mL, 10 mL, 50 mL, 500 mL, etc. When in use, the measured liquid should be injected into the graduated cylinder to keep the sight level with the lowest part of the concave surface of the liquid in the graduated cylinder, and then read The scale on the graduated 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, be careful not to touch or insert the dropper on the wall or inside of the receiving container.
Chemical reagent access rules
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 deteriorating:
(1) The reagent should not be in contact with the hand.
(2) Use clean medicine spoons, graduated cylinders or droppers to take reagents. Never use the same tool to take multiple reagents continuously. After taking one reagent, the tools should be washed (the spoon should be wiped dry) before taking another reagent.
(3) Be sure to close the bottle stopper tightly after taking the reagent. Do not put the wrong bottle cap and dropper on the bottle. Never put a crown on or wear it. Put the bottle back to its original place after use.
(4) Reagents that have been taken out cannot be put back into the original reagent bottle.
In addition, the reagents should be used in the spirit of economy and use as little as possible. This is convenient for operation and careful observation of phenomena, and better experimental results can be obtained.
Precautions for storage of chemical reagents
1. seal:
Most reagents must be sealed and stored, and the following 3 types stand out:
①Easily volatile reagents, such as concentrated hydrochloric acid, concentrated nitric acid, concentrated bromine water, etc.
②Reagents that easily interact with water vapor and carbon dioxide, such as anhydrous calcium chloride, caustic soda, water glass, etc.
③Reagents that are easily oxidized (or reducing reagents), such as sodium sulfite, hydrogen sulfuric acid, ferrous sulfate, etc.
2. Protect from light:
Reagents that are easily decomposed by exposure to light or heat should be kept away from light and kept in a cool place, such as nitric acid and silver nitrate. Generally, they should be placed in a brown reagent bottle.
3. Corrosion protection:
For corrosive reagents, pay attention to corrosion prevention. For example, hydrofluoric acid can not be placed in glass bottles; strong oxidants and organic solvents cannot be stored in reagent bottles with rubber stoppers; lye, water glass, etc. cannot be used with glass stoppers The reagent bottle is stored.
4. inhibition:
For reagents that are easy to be hydrolyzed and oxidized, some substances must be added to inhibit their hydrolysis or oxidation. For example, a small amount of hydrochloric acid is often dropped into the ferric chloride solution; a small amount of iron filings is often added to the ferrous sulfate solution.
5. isolation:
For example, flammable organics should be kept away from fire sources; strong oxidizers (peroxides or oxyacids and their salts with strong oxidizing properties) should be stored separately from easily oxidized substances (carbon powder, sulfide, etc.).
6. ventilation:
The storage of most reagents should follow this principle. Especially flammable organics, strong oxidants, etc.
7. Low temperature:
For reagents that are prone to reaction at room temperature, measures should be taken to store them at low temperature. For example, unsaturated hydrocarbons and derivatives such as styrene and methyl acrylate are prone to polymerize at room temperature, and hydrogen peroxide is prone to decomposition, so the temperature should be below 10°C. Environmental preservation.
8. special:
Special reagents should be preserved by special measures. For example, potassium and sodium should be placed in kerosene, and white phosphorus should be placed in water; liquid bromine is very volatile and should be covered with a layer of water.
Access to chemical reagents
The solid powder reagent can be taken with a clean horn spoon. To take a certain amount of solids, put the solids on paper or watch glass and weigh them on a platform scale. For accurate weighing, use a weighing bottle to weigh on the balance. Liquid reagents are usually measured in graduated cylinders. The capacities of the graduated cylinders are: 5 mL, 10 mL, 50 mL, 500 mL, etc. When in use, the measured liquid should be injected into the graduated cylinder to keep the sight level with the lowest part of the concave surface of the liquid in the graduated cylinder, and then read The scale on the graduated 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, be careful not to touch or insert the dropper on the wall or inside of the receiving container.
Chemical reagent access rules
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 deteriorating:
(1) The reagent should not be in contact with the hand.
(2) Use clean medicine spoons, graduated cylinders or droppers to take reagents. Never use the same tool to take multiple reagents continuously. After taking one reagent, the tools should be washed (the spoon should be wiped dry) before taking another reagent.
(3) Be sure to close the bottle stopper tightly after taking the reagent. Do not put the wrong bottle cap and dropper on the bottle. Never put a crown on or wear it. Put the bottle back to its original place after use.
(4) Reagents that have been taken out cannot be put back into the original reagent bottle.
In addition, the reagents should be used in the spirit of economy and use as little as possible. This is convenient for operation and careful observation of phenomena, and better experimental results can be obtained.
Precautions for storage of chemical reagents
1. seal:
Most reagents must be sealed and stored, and the following 3 types stand out:
①Easily volatile reagents, such as concentrated hydrochloric acid, concentrated nitric acid, concentrated bromine water, etc.
②Reagents that easily interact with water vapor and carbon dioxide, such as anhydrous calcium chloride, caustic soda, water glass, etc.
③Reagents that are easily oxidized (or reducing reagents), such as sodium sulfite, hydrogen sulfuric acid, ferrous sulfate, etc.
2. Protect from light:
Reagents that are easily decomposed by exposure to light or heat should be kept away from light and kept in a cool place, such as nitric acid and silver nitrate. Generally, they should be placed in a brown reagent bottle.
3. Corrosion protection:
For corrosive reagents, pay attention to corrosion prevention. For example, hydrofluoric acid can not be placed in glass bottles; strong oxidants and organic solvents cannot be stored in reagent bottles with rubber stoppers; lye, water glass, etc. cannot be used with glass stoppers The reagent bottle is stored.
4. inhibition:
For reagents that are easy to be hydrolyzed and oxidized, some substances must be added to inhibit their hydrolysis or oxidation. For example, a small amount of hydrochloric acid is often dropped into the ferric chloride solution; a small amount of iron filings is often added to the ferrous sulfate solution.
5. isolation:
For example, flammable organics should be kept away from fire sources; strong oxidizers (peroxides or oxyacids and their salts with strong oxidizing properties) should be stored separately from easily oxidized substances (carbon powder, sulfide, etc.).
6. ventilation:
The storage of most reagents should follow this principle. Especially flammable organics, strong oxidants, etc.
7. Low temperature:
For reagents that are prone to reaction at room temperature, measures should be taken to store them at low temperature. For example, unsaturated hydrocarbons and derivatives such as styrene and methyl acrylate are prone to polymerize at room temperature, and hydrogen peroxide is prone to decomposition, so the temperature should be below 10°C. Environmental preservation.
8. special:
Special reagents should be preserved by special measures. For example, potassium and sodium should be placed in kerosene, and white phosphorus should be placed in water; liquid bromine is very volatile and should be covered with a layer of water.
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