论文部分内容阅读
焰色反应是指某些金属或它们的化合物在灼烧时使火焰呈现特殊颜色的反应。教材(人教版新课标必修1)中钾元素的焰色反应实验采用将铂丝蘸取少量溶液在酒精灯火焰上灼烧的方法。该方法存在以下缺点:①铂丝蘸取的盐量少,灼烧时钾元素的特征焰色持续时间短;②观察钾元素的紫色火焰时需透过蓝色钴玻璃片,而且要将观察视线调到一定角度;③该实验操作复杂,实验前后铂丝都要进行清洗。为了克服以上缺点,我们采用了一种新的实验方法。实验步骤: (1)取少量KNO_3晶体放入坩埚中,向坩埚中加入1mL水,用一干净的玻璃棒搅拌使KNO_3晶体溶
Flame reaction refers to the reaction of certain metals or their compounds that cause the flame to exhibit a special color when it is burned. The flame reaction experiment of potassium in the textbook (Public Education New Curriculum Standard 1) adopts the method of burning a small amount of platinum wire on the flame of an alcohol lamp. This method has the following disadvantages: 1 The amount of salt extracted by the platinum wire is small, and the flame duration of the characteristic element of potassium is short at the time of burning; 2 The blue flame of cobalt is required to pass through the blue cobalt glass when observing the purple flame of potassium. The line of sight is adjusted to a certain angle; 3 The experiment is complicated and the platinum wire must be cleaned before and after the experiment. In order to overcome the above drawbacks, we have adopted a new experimental method. Experimental procedure: (1) Take a small amount of KNO 3 crystal into the crucible, add 1 mL of water to the crucible, stir with a clean glass rod to dissolve the KNO 3 crystal.