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长期以来,统编教材都采用萘来做晶体的熔解和凝固实验。但由于萘的熔点较高,致使实验时间较长,影响教学进度;又因采用酒精灯给水(再给萘)加热,实验装置较复杂,且温度不易控制,致使熔解曲线不甚理想,不利于学生对晶体熔解特性的理解;另外,萘的气味对人有刺激,而且实验后试管中萘的回收和清理也比较困难。若采用海波(硫代硫酸钠)代替萘进行实验,上述缺点便可得到有效的克服。兹介绍如下。一、实验装置左图是用海波做晶体熔解和凝固实验的
For a long time, the textbook has used naphthalene as a crystal melting and solidification experiment. However, due to the higher melting point of naphthalene, the experimental time is longer, which affects the progress of teaching; because of the use of alcohol lamp water (naphthalene) heating, the experimental device is more complex, and the temperature is not easy to control, resulting in the melting curve is not ideal, is not conducive to The understanding of crystal melting characteristics of students; In addition, the smell of naphthalene is irritating to humans, and the recovery and cleaning of naphthalene in test tubes is also difficult. If Haibo (sodium thiosulfate) is used instead of naphthalene for experiments, the above disadvantages can be effectively overcome. This is described below. First, the experimental device left picture is to use the sea wave for crystal melting and coagulation experiments