赓续冬奥冰雪情 运动化学两相宜——利用“电子滑雪法”认识氧化还原反应中的能量变化

Comprehensive and Dynamic Perspective to Study Redox Reactions by Energy Exchange

氧化还原反应集合了转化观、能量观、元素观、守恒观等多个基本思想,是高中化学教学中的重点和难点。笔者发现在学习氧化还原反应时,学生常常出现明显的思维定式,缺乏对化学新情境的认识思路。正确判断电子转移过程是分析氧化还原反应的基础,深入理解反应条件和能量变化是实现能力迁移的前提。受到自由能-氧化态图的启发,笔者以滑雪运动进行类比,从能量变化角度分析氧化还原反应,旨在深化学生对化学学科本质的认识,推动高阶思维能力的成长,同时为教师提供探究式和建构式的教学参考。

Redox reaction is a vital section in high school chemistry course framework,which connects the knowledge of structure and property,transformations and energy transfer tightly.When analyzing a redox reaction,the most important thing is to identify the electron transfer in the reactants,and then to determine the reasonable energy exchange during the reaction.We find it is a common difficulty for beginners or even senior students to apply redox reaction in a novel circumstance.Herein,we show how to use the Frost diagram to analyze redox reactions that involve several tricky elements including Fe,Mn,N,S and Cl.We compare the electron transfer process with sking,to elucidate the variation of reactants and energy in a spontaneous reaction.We assume it is a powerful strategy for high school chemistry teachers and students to analyze the redox reactions more effectively and understand the transformations in a more comprehensive and dynamic perspective.