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一、实验改进的目的Ba(OH)_2·8 H_2O与NH_4Cl的吸热反应实验是人教版必修2第34面的实验。按教材所示进行操作,存在以下不足:若玻璃片上滴水过少,在室温较高时,拿起烧杯,会让冰融化,玻璃片易掉下造成危险;另外,演示实验时,学生无法看清水的结冰状况。为解决这些问题,笔者对实验步骤与用品进行了改进,得到了明显的实验现象与较好的教学效果。二、实验步骤1.取一支小试管,装2 mL水,滴加1滴红墨水(显色)。
First, the purpose of experimental improvement Ba (OH) _2.8H_2O and NH_4Cl endothermic reaction test is the PEP 2 compulsory 34th experiment. According to the teaching materials shown in the operation, there are the following deficiencies: If the drip on the glass is too small, at room temperature is high, pick up the beaker, the ice will melt, the glass is easy to fall cause danger; In addition, demonstration experiments, students can not see Fresh water icing conditions. In order to solve these problems, the author improved the experimental procedures and supplies, and obtained obvious experimental phenomena and better teaching effects. Second, the experimental steps 1. Take a small test tube, install 2 mL of water, add 1 drop of red ink (color).