初中化学演示实验中，常常由于试剂的选择和操作步骤不当，而使实验失败，影响教学效果。下面谈一点粗浅体会。一、演示中应正确地选择试剂演示中根据不同的反应和试剂的特点正确选择试剂是保证演示成功不可忽视的因素。例如：１、实验室里制取ＣＯ２气体时，酸的最佳选择... In chemistry demonstration experiments in junior high schools, due to improper selection and operation procedures of reagents, the experiment fails and affects the teaching effect. Let’s talk about a little superficial experience. First, the correct selection of reagents in the demonstration should be based on different reactions and the correct selection of reagents to ensure the success of the demonstration can not be ignored factors. For example: 1. The best choice of acid in the preparation of CO2 gas in the laboratory...