Precautions for the use and operation of chemical instruments

What a chemical instrument, it has to have a name!

1) Test tubes. Main Applications:

Under normal temperature or heating conditions, it is used as a reaction vessel for a small amount of reagents.

Purification of small amounts of gas and gases.

How to use and precautions:

It can be heated directly, and the test tube clamp is clamped at 1 3 places away from the test tube mouth.

The size of the test tube can be large or small. The liquid in the tube does not exceed the volume 1 3.

The outer wall should be free of water droplets before heating; It should not be quenched after heating to prevent the tube from rupturing.

When heated, the mouth of the test tube should not be directed at anyone. When heating the solids, the tube should be placed horizontally with the nozzle slightly inclined downward.

It is not possible to use a test tube to heat and melt strong alkaline substances such as NaOH.

2) Evaporation dish.

Main uses: evaporation, concentration, crystallization of solutions.

Dry solid matter.

How to use and precautions:

The volume of liquid does not exceed 2 3 of the volume.

It can be heated directly, and cannot be quenched after heating.

The evaporation dish should be accessed using crucible forceps.

2.The pad asbestos mesh can be heated.

1) Beaker. Main Applications:

It is used as a container for dissolving solid substances and diluting liquids.

It is used as a vessel for reactions with larger amounts of reagents.

A cold, dry beaker can be used to test whether water is formed during gas combustion; A beaker coated with clarified lime water can be used to test CO2 gas.

How to use and precautions:

Commonly used specifications are 50ml, 100ml, 250ml, etc., but do not use a beaker to measure liquid;

It should be placed on an asbestos net to heat it evenly; When heated, the outer wall of the beaker should be free of water droplets.

When the liquid is heated, it is generally advisable not to exceed 1 2 of the beaker volume.

During dissolution or dilution, stir with a glass rod without touching the bottom or walls of the cup.

2) Flasks. Main Applications:

It can be used as a reaction vessel with a large amount of reagent and liquid participation, and is often used in various gas generators. Distillation flasks are used to separate liquids that are miscible and have large differences in boiling points.

How to use and precautions:

It should be placed on an asbestos net to heat it evenly; When heating, the outer wall of the flask should be free of water droplets;

Flat-bottomed flasks cannot be used for long periods of time to heat;

3) Erlenmeyer flask.

Main use: It can replace test tubes, flasks, etc. as a gas generation reactor.

How to use and precautions: When heating, asbestos mesh needs to be padd.

3.It cannot be heated.

In chemical experiments, safety comes first, and the following are some precautions for chemical experiments

1.Wear personal protective equipment: such as lab coats, gloves, goggles, etc.

2.Familiarity with experimental procedures and principles: Before conducting experiments, you should be familiar with the experimental procedures and corresponding reaction principles.

3.Pay attention to the experimental conditions: such as temperature, pressure, pH, etc., these conditions may affect the experimental results.

4.The cap should be tight: During the experimental operation, the cap should be closed tightly to avoid volatilization or leakage of the reagent.

5.Adhere to the principle of quantity accuracy: use equipment such as balances and volumetric instruments to weigh and pipette accurately.

6.Cooling with water or adding diluent: When it is necessary to add reagents such as concentrated sulfuric acid scattered field and concentrated hydrofluoric acid that are prone to high thermal reaction, it should be cooled with water before adding or adding diluent.

7.Avoid mixing incompatible substances: such as chloric acid and glycerin, chloric acid and carbon and other substances that can easily lead to ** cannot be mixed.

8.Do a good job of cleaning after the experiment: After the experiment is completed, clean the test tubes, beakers, containers, etc. and place them in the designated place.

In conclusion, chemical shooting or experimental operation needs to pay attention to safety, accuracy and standardization. At all times, it is necessary to strictly abide by the experimental principles and procedures, keep it clean and tidy, and do a good job of system management and maintenance of reagents and equipment. This is the only way to minimize the risk of experiments and obtain accurate and reliable results.