论文部分内容阅读
高一化学中金属元素的焰色反应,通常用铂丝进行实验。这一实验存在下列一些困难:一是对一般学校来说,铂丝来源困难,学生分组实验更难以办到。若用铁丝代替,效果较差。二是现象不明显,由于酒精灯火焰呈黄色,钾火焰须隔钴玻璃才能观察到。除铜元素外,其它焰色难以分辨。本人对这一实验进行了改革,方法是用洁净的脱脂棉代替铂丝进行实验。操作时只需取紧缩成比大豆稍大一点的脱脂棉球,在无水酒精中湿润,将被检验的含某金属元素的盐类粉末洒少量于棉球上,然后用镊子夹其1/3处,在酒精灯上点燃,迅速离开。此时在燃烧的棉
The flame reaction of metal elements in the chemistry of high-grade chemistry usually uses platinum wire for experiments. This experiment has the following difficulties: First, for ordinary schools, the source of platinum wire is difficult, and it is even more difficult for students to group experiments. If you use iron wire instead, the effect is poor. Second, the phenomenon is not obvious. Since the flame of the alcohol lamp is yellow, the potassium flame must be observed in the cobalt glass. In addition to copper, other flame colors are difficult to distinguish. I have reformed this experiment by using clean cotton wool instead of platinum wire for experiments. During the operation, it is only necessary to take a defatted cotton ball that is slightly larger than soy beans, moistened with anhydrous alcohol, and sprinkle a small amount of the salt powder containing a certain metal element to be tested on the cotton ball, and then clamp it with tweezers. Ignite on an alcohol lamp and leave quickly. At this point in the combustion of cotton