初中化学“酸和碱的性质”创意教学——探析食品发热包

Creative Teaching of“Properties of Acids and Bases”in Junior High School Chemistry:Analysis of Food Self-Heating Bag

以食品发热包为主题情境,通过探析发热包成分、解密发热原理、计算原料配比、配制发热包等环节梳理酸和碱的性质、用途。从元素观、转化观的视角认识物质转化规律,体现物质研究的一般思路,凸显科学探究的基本过程。通过设计方案测定发热包中碳酸钠的含量,总结混合物成分鉴定及定量测定的方法;归纳气体定量测定的影响因素。呈现一堂学科观念、学科方法教学具体课例,凸显物质研究、定性检验、定量测定的基本方法。

This lesson takes food self-heating bag as the theme,reviews the properties and uses of acids and bases by analyzing the components of the self-heating bag,deciphering the heating principle,calculating the proportion of raw materials,preparing self-heating bags.From the perspective of transformation view and element view to understand the law of material transformation,the general ideas of material research and the basic process of scientific inquiry are highlighted and shown.The methods of composition identification and quantitative determination of the mixture are summarized through the design of experimental scheme to determine the content of sodium carbonate in the self-heating bag.The influencing factors of gas quantitative determination are summarized.This paper presents a specific teaching example of subject concept and subject method,and highlights the basic methods of material research,qualitative inspection and quantitative determination.