一、教材分析本节课选自人教版初中化学九年级下册第九单元“溶液”课题1“溶液的形成”第二课时“溶解时的吸热或放热现象”的内容,其“探究”是对溶液的概念和形成等知识的延伸和扩展,同时为后面学习溶解度和溶质的质量分数奠定一定的基础,起到承上启下的作用。从结构上看,本单元是整个初中化学的重点内容,是学习第十中元中浓硫酸和氢氧化钠的相关性质的重要基础,呈现出知识的循序渐进和螺旋式上升的结构特点,同样具有承上启F的过渡作用。从意义上,本节课的内容有利于提A乍生将化学知识应用丁生产、生活实践的意识,感受化学与科技的密切关系 First, the textbook analysis This lesson was selected from the PEP Junior High School Chemistry ninth volume ninth unit “solution ” topic 1 “solution formation ” the second class “dissolution of endothermic or exothermic phenomenon The content of ”Inquiry" is an extension and expansion of the concept of the solution and the formation of knowledge, at the same time, it provides a basis for learning the solubility and the mass fraction of the solute, which plays a role in bearing on. From a structural point of view, this unit is the focus of the entire junior high school chemistry, is learning the tenth meta-concentrated concentrated sulfuric acid and sodium hydroxide related to the important basis of the nature of showing a gradual and spiral knowledge of the structural features of the same Accept the transition from F to F. In a sense, the content of this lesson is conducive to mentioning A-Shah’s awareness of applying chemical knowledge to small-scale production and living practices and the close relationship between chemistry and science and technology