Operation of preheating test tube

The operation steps of pipe preheating are as follows:

1. Preparation and safety precautions

Tube preheating is one of the common operation steps in chemical experiments, which is used to avoid the risk of tube breakage caused by sudden temperature rise when heating the tube.

When preheating the test tube, you need to make the following preparations and precautions: wear necessary personal protective equipment, such as experimental gloves and goggles, in the laboratory. Ensure that the workbench is clean and tidy, and there are no inflammable or other dangerous goods. Check whether the heating equipment works normally and whether the power supply is well grounded.

Clean test tube

Before preheating the test tube, thoroughly clean the test tube to ensure that there are no impurities or residues in it that will affect the experimental results. The steps of cleaning test tubes are as follows: take a certain number of test tubes and put them into the cleaning tank. Add a proper amount of cleaning agent such as dilute hydrochloric acid. Thoroughly clean the inner wall of the test tube with a tube brush or cotton swab. Rinse the test tube with pure water until there is no detergent residue in the test tube.

3. Choose the right heating equipment

According to the needs of the experiment and the capacity of the test tube, choose the appropriate heating equipment to preheat the test tube. Common heating equipment includes alcohol lamp, gas lamp, electric heating plate, etc.

When choosing heating equipment, the following factors should be considered: heating speed: according to the experimental requirements, choose heating equipment with faster or slower heating speed. Temperature control: If you need to control the temperature of the test tube heating, you can choose a heating device with temperature control function. Safety: Choose heating equipment with good stability, simple operation and high safety.

4. Test tube preheating operation

Next, preheat the test tube: clamp the test tube to be preheated on the test tube clamp to ensure the contact area between the test tube and the clamp is large. If alcohol lamp or gas lamp is used, ignite the flame and put the test tube in the flame so that the whole bottom of the test tube is evenly heated.

If an electric heating plate is used, turn on the power supply, adjust the heating temperature, and place the test tube in the center of the heating area. According to the experimental requirements, the test tube is preheated for a proper time, usually a few minutes. After preheating, quickly take out the test tube and clamp the upper part of the test tube to avoid scalding.

Through the above steps, we can preheat the test tube safely and effectively. The preheated test tube can be used for various experiments, such as heating reaction and dissolving solids. However, it should be noted that care should be taken when preheating the test tube to avoid accidents.