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近年来介绍“差量法”解计算题的文章和习题很多。此法是以《质量守恒定律》为依据,解法简捷,但大部分学生开始接触此法时,觉得不易掌握。我就结合实验分析这类题目,介绍“差量法”计算,收到较好的效果。现将具体做法介绍如下: 题目:在盛有30克稀硫酸的锥形瓶中投入7克锌粒,反应完毕后,锥形瓶和内容物的总质量增加了6.8克,求生成硫酸锌多少克? 边演示边分析:在两只锥形瓶内分别注入30克水和30克稀硫酸,先向盛水的锥形瓶中投入?克锌粒,等一会儿问,锥形瓶及内容物的总质量增加多少克?(7克),溶液质量有无变化,为什
In recent years, many articles and exercises have been introduced to the “Differential Method” solution. This method is based on the “law of conservation of quality” and the solution is simple and straightforward. However, most students find it difficult to grasp when they begin to approach this method. I analyzed this type of problem by combining experiments and introduced the “Differential Method” calculation to receive better results. The specific practices are described as follows: Title: 7 grams of zinc are put into a conical flask containing 30 grams of dilute sulfuric acid. After the reaction, the total mass of the conical flask and the contents is increased by 6.8 grams. How much zinc sulfate is generated? Sample analysis: While injecting 30 g of water and 30 g of dilute sulfuric acid into two Erlenmeyer flasks, put ?g of Zinc into a conical flask filled with water and wait for a while to ask. Conical flasks and contents How many grams of total mass increase (7 grams) does the solution quality change?