A: The instrument washing steps are as follows:

(1) Wash with tap water. Why is the first laboratory suitable for glass instruments? What are the commonly used glass instruments?

Answer: (1) A large number of glass instruments are used in the laboratory because the glass has a series of valuable properties, it has high chemical stability and thermal stability, has good transparency, has certain mechanical strength and good insulation properties. The raw materials are convenient and can be made into products of various shapes.

(2) There are two kinds of instrument glass commonly used in laboratories, namely potassium glass and hard glass. Potassium glass is mainly composed of SiO2, CaO, K2O, A12O3 and B203, and is commonly used in the production of glass tubes, funnels, dryers, burettes and other non-heat resistant glass instruments. Hard glass (nine-five material) contains higher SiO2 and B203, higher temperature resistance than potassium glass, especially the resistance to quenching and rapid heat is better than potassium glass, and is often used to make temperature-resistant instruments such as beakers and flasks.

It is first required to rinse off the impurities inside and outside the glass instrument with a larger amount of water, and then wash it with a suitable brush so that the eyes cannot see the presence of other substances and colors on the instrument.

(2) Wash with washing solution. There are many kinds of washing liquids for glass washing instruments, mainly organic washing liquids and inorganic washing liquids, and inorganic washing liquids are further divided into acidic and alkaline washing liquids. When washing, pay attention to the water in the glass instrument, then pour a small amount of washing liquid, and slowly rotate it obliquely, so that the inner wall of the instrument is completely wetted by the washing liquid. After rotating back and forth several times, pour the washing liquid into another A glass instrument to be washed.

(3) Rinse with tap water. Rinse the glass instrument with plenty of tap water and wash off the lotion inside and outside the glass instrument. (4) Finally, wash with distilled water. The principle of washing glass instruments with distilled water is a small number of times. Since distilled water is not easy to reach, and it is required to clean the glass instrument, it is washed several times with a small amount of water, and at least three times. The inner surface of the glass instrument should be washed when washing, and the cleaned glass instrument must be bright and smooth. The main sign of instrument washing is that when the glass instrument is inverted, the water should flow out after the water is discharged.

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