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一、阿佛加德罗常数的测定阿佛加德罗常数是一个重要的物理常数。测定它的方法有多种,教材采用硬脂酸形成单分子膜的方法,设备简单,操作简易,费时不多,适合中学生特点。但由于实验数据较多,引起误差的因素也就较多,故不易获得精确结果。在一般中学的实验条件下,能获得5×10~(23)至7×10~(23)就是较为理想的数据了。实验过程中,如下几点值得注意。1.关于硬脂酸苯溶液的制备硬脂酸最好用分析纯,也可用化学纯。苯中有少量水,可用无水氯化钙或氧化钙除去。
A. Determination of Avogadro’s Constant The Avogadro’s constant is an important physical constant. There are many ways to determine it. The teaching materials use stearic acid to form monomolecular membranes. The equipment is simple, easy to operate, and time-consuming. It is suitable for middle school students. However, due to the large number of experimental data, there are many factors that cause errors, so it is not easy to obtain accurate results. Under the experimental conditions of general secondary schools, obtaining 5×10 23 to 7×10 23 is the ideal data. During the experiment, the following points are worth noting. 1. Preparation of Stearic Acid Benzene Solutions Stearic acid is preferably analytically pure or chemically pure. There is a small amount of water in benzene that can be removed with anhydrous calcium chloride or calcium oxide.