1.选用药品首先要考虑反应速度。因为实验室制取的气体主要用于某些性质实验,用量较少,一般要求反应速度快,而且不要高温高压等一系列困难的条件。如实验室制氨采用固体氯化铵和固体消石灰混和共热的方法,而不用氮气和氢气合成氨的方法。 2.选用药品要以经济为原则。也就是说尽可能地使用哪些价格比较便宜的药品。如制 1. The first thing to consider when choosing drugs is to consider the reaction rate. Because the gas produced by the laboratory is mainly used for certain nature experiments, the amount is less, generally require a fast reaction speed, and does not require a series of difficult conditions such as high temperature and high pressure. For example, ammonia in the laboratory uses a method in which solid ammonium chloride and solid slaked lime are mixed and heated together instead of nitrogen and hydrogen to synthesize ammonia. 2. The use of drugs should be based on economic principles. That is to say, which cheaper medicines are used as much as possible. As