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多年来,在高中和大学无机化学实验中,一直存在着一些常见的但始终未能彻底解决的问题。譬如,Fe~(2+)在空气中被氧化的速度与介质的酸碱性的关系问题,用KClO_3热分解法制氧时MnO_2的催化作用问题;用锌粒和稀硫酸作用制氢时,残余锌粒上附着的黑色物质是什么东西?为什么在制取氨气的实验中,当加热氢氧化钙和氯化铵的固体混合物时会在试管壁上出现黄色物质?等等这些问题虽然不能说是化学上的未解之谜,但是长期没能得到合理的解释,当学生请求解释这些“怪现象”时,多数老师也只能告诉学生这些问题的发生是杂质所致。其实,教师本人对这
Over the years, there have been some common problems that have not been completely solved in inorganic chemistry experiments in high schools and universities. For example, the relationship between the rate of oxidation of Fe 2+ in the air and the acidity and alkalinity of the medium, the catalysis of MnO 2 during the oxygen production by the KClO 3 thermal decomposition method, and the remnant during the production of hydrogen by the action of zinc particles and dilute sulfuric acid. What is the black matter attached to the zinc particles? Why does the problem occur when the ammonia mixture is heated in a solid mixture of calcium hydroxide and ammonium chloride on the wall of the test tube? It is a chemical mystery, but it has not been reasonably explained for a long time. When students ask to explain these “strange phenomena”, most teachers can only tell students that these problems are caused by impurities. Actually, the teacher himself