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中学化学课中常用焰色反应的方法来定性鉴别K~+、Na~+、Ca~(++)、Ba~(++)、Li~+、Sr~(++)、Cu~(++)等离子,但在实验过程中现象往往不明显。其原因有以下几个方面: (1)酒精灯的火焰温度较低(约500℃)使有些离f的焰色不明显,如Ca~(++)、Ba~(++)等。 2)酒精灯火焰呈黄色,干扰了一些离子的焰色反应。 3)学生实验过程中不严格按操作规程做,易互相干扰,鉴别困难。除现象不明显外,用价格昂贵的铂丝不经济,学生易损坏,造成很大浪费。根据上述情况,既要达到现象明显又要经济,在
Flame reaction method commonly used in middle school chemistry class to qualitatively identify K~+, Na~+, Ca~(++), Ba~(++), Li~+, Sr~(++), Cu~(+ +) Plasma, but the phenomenon is often not obvious during the experiment. The reasons are as follows: (1) The lower flame temperature of the alcohol lamp (about 500°C) makes some of the flames from the f, such as Ca ++, Ba ++, etc. 2) The flame of the alcohol lamp is yellow, which interferes with the flame reaction of some ions. 3) Students do not strictly follow the operating procedures during the experiment, and they easily interfere with each other and identify difficulties. In addition to the phenomenon is not obvious, the use of expensive platinum wire is not economical, students are vulnerable to damage, resulting in a lot of waste. According to the above situation, it is necessary to achieve phenomenal and economical