How to use test tubes and other instruments and matters needing attention
1. The reaction solution should not exceed 1/2 of the volume of the test tube, and should not exceed 1/3 during heating.
2. The outside of the test tube should be wiped dry before heating, and the test tube clamp should be used to clamp it during heating.
3. When heating the liquid, do not face the mouth of the tube, tilt the test tube and the table at 45 degrees, and keep shaking at the same time. The upper end of the flame cannot exceed the liquid level in the tube.
4. When heating solids, the nozzle is slightly inclined downward.
5. The centrifuge tube can only be used for heating in a water bath.
6. The hard test tube can be heated to high temperature, but should not be quenched. The flexible test tube can easily break when the temperature changes sharply.
7. Generally, the large test tube is heated directly, and the small test tube is heated in a water bath.
When preparing solutions, dissolving samples, etc., the beaker should be placed on the asbestos mesh to make it heated evenly and generally not dry.
Heat treatment and volumetric analysis titration of conical flask samples In addition to the same requirements as above, the stopper of the conical flask should be opened when it is heated, and the original stopper should be retained for non-standard grinding.
Iodine bottle iodometric method or quantitative analysis of other volatile substances, ibid.
Round (flat) bottom flask heating distilled liquid generally avoid direct fire heating, asbestos mesh heating or heating of various heating baths.
Distilled in a round-bottomed distillation flask; it can also be used as a small gas generating reactor, ibid.
Kjeldahl flasks digest organics. Place the asbestos mesh to heat. Don't confront yourself and others.
