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现行高中课本《化学》第二册(必修)第2O页实验[2—2]是铝热反应的实验,该实验是让镁条经燃烧,放出一定的热量,使氧化铁粉末和铝粉在较高的温度下发生剧烈的反应。但如果按教材要求去做,用小木条点燃镁条,实际做起来比较难,如果用酒精灯倾斜去点燃镁条,又不符合实验操作规则。为此,我对实验中镁条点燃的方法进行了改进。 1.取长约10cm的一段镁条,用砂纸擦去其表面的氧化膜。 2.用坩埚钳夹住镁条的中间部位,在燃着的酒精灯上点燃,待其燃烧后,竖直地插入铝热剂中,然后移开坩埚钳。 这样点燃镁条一燃就着,实验成功率高。
The current high school textbook “Chemistry” Book 2 (required) page 2O experiment [2-2] is an experiment of the aluminothermic reaction. The experiment is to burn the magnesium bar and release some heat, so that the iron oxide powder and aluminum powder are Severe reactions occur at higher temperatures. However, if it is done according to the requirements of the teaching materials, using a small piece of wood to ignite the magnesium bar, it is actually more difficult to do it. If the alcohol lamp is tilted to ignite the magnesium bar, it does not comply with the experimental rules. For this reason, I improved the method of igniting magnesium in the experiment. 1. Take a piece of magnesium strip about 10cm long and wipe off the oxide film on the surface with sandpaper. 2. Use a forceps to clamp the middle part of the magnesium strip and ignite it on a burning alcohol lamp. After it is burned, insert it into the aluminum heat medium vertically. Then remove the forceps. This kind of igniting the magnesium bar burns, and the experimental success rate is high.