Some common mistakes in glass instruments
[China Glass Network] First, the mistakes in the washing of glass instruments 1. The cleaning of glass instruments is the front step of the inspection work. In practice, many people often neglect to clean the glassware used immediately before and after the inspection, or to clean the appliance. As a result, the inner wall of the appliance is heavily hung with water droplets, dirt, and precipitated dry matter adhered to the inner wall, etc., which cannot be cleaned, directly affecting the accuracy of the data. Want to be trendy and just blindly follow popular logo? You can't be more wrong! The same style actually has a lot of more cost-effective products to choose from, our golden monkey shoes, fashion is not inferior to international brands and popular logo, and with more solid materials, more reasonable price! Women's High Heels,Women's Sneakers,Women's Sandals,Women's Single Shoes GDMK GROUP WEIHAI SHOES CO., LTD. , https://www.gdmkgroup.com
2. There are many varieties and items in general quality inspection. It is impossible to use a set of special instruments for each indicator. It is often used alternately, and the instruments used are not strictly cleaned or cleaned. It will inevitably cause alternating contamination between reagents. Thereby affecting the accuracy of the test results.
3. On the other hand, the capacity measuring tool is mixed with the non-capacity measuring tool property and the washing method, and both are washed with the decontamination powder, which causes the capacity of the measuring device to be inaccurate and affects the accuracy of the measurement result.
Second, the error in the heating of the glass container
1. The heating process is a common step in physical and chemical analysis. In actual work, some people often ignore or simply can't figure out which instruments can be heated, and even make mistakes. In fact, glass containers are not directly heated, such as measuring cylinders, measuring cups, volumetric flasks, reagent bottles, etc. can not be directly heated. Reaction vessels such as beakers, flasks, and flasks should be used as appropriate. If the basic knowledge is not known in the actual work, there will be errors and even inspection accidents.
2. When heating the glass container, the container is not placed on the asbestos net, but the container is placed directly in the electric furnace, so that the container is unevenly heated or even bursts.
3. During use, the temperature changes too much, or the hot glass container that is quenched or removed at high temperature is placed directly on the table, and is not placed on the asbestos net as required, causing the container to rupture and the reagents to be lost, which may affect the normal operation of the inspection. .
4. In actual work, some people are afraid of trouble and are not accustomed to using the dryer properly. For the heating device that needs accurate weighing, it should be dried and taken out slightly cold (about 30s), put into a desiccator and cooled to room temperature for weighing ( 30min can be). When the warm appliance is placed in the dryer, leave a gap in the cover and wait a few minutes to cover it tightly; when moving the dryer, you should not only lower the lower part, but hold the cover to prevent the cover from slipping, causing no The necessary loss.
Third, the mistakes in the selection and use of glass containers
Accurate measurement of the volume of a solution in a volumetric analysis is an important factor in obtaining good analytical results. Therefore, it is necessary to correctly use the volumetric instruments, such as burettes, pipettes, volumetric flasks, etc., and there are often some errors in actual operation.
1. The acid burette and the basic burette cannot be correctly distinguished and their properties. The acid burette is often mistaken for the basic burette during use; the basic burette is mistaken for the acid burette. This is a mistake. Because the acid burette has a glass piston at the lower end, it cannot hold an alkaline solution because the alkaline solution can corrode the glass. Rotate the piston. The bottom of the basic burette is connected with a rubber tube, and can not contain a solution of corrosion rubber such as acid or oxidant, such as AgNO3, KM-nO4, I2 and the like.
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