初中课本 P110[实验3—5]如果照书中所说进行实验,指针移动极微,现象很不明显。这是什么原因呢?主要是托盘天平灵敏度小,烧杯的质量大、体积小,如果把250毫升烧杯中的空气全部换成二氧化碳,也仅增加0.169克,而且实际上用排气法收集的气体不可能很纯,再加上要通过集气瓶倾倒入烧杯中,这样烧杯的实际增重一般不足0.1克。在几十 Junior high school textbooks P110 [Experiment 3-5] If the book said that the experiment, the pointer movement is minimal, the phenomenon is not obvious. This is why? Mainly small tray balance sensitivity, quality beaker, small size, if the 250 ml beaker of air all replaced by carbon dioxide, only increased 0.169 grams, and in fact collected by the exhaust gas Can not be pure, coupled with dumping into the beaker through the gas collection bottle, so the actual weight of the beaker is generally less than 0.1 grams. In dozens