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物质鉴别题是化学中考的常见题型之一,它主要是根据几种物质的不同特性来——弄清它们各是什么物质。现结合实例谈谈常见的几种题型及解法。1 任选试剂的鉴别题 解这类题一般先分析给定物质的组成、类别及特性,选择恰当的试剂按其共性分组,然后按个性逐个将它们鉴别出来。 例1 四瓶无色溶液,它们分别是氯化钾、碳酸钠、硝酸钾和硫酸钾,怎样鉴别它们? 分析:由于这四种溶液都是无色透明溶液,无法用物理性质会鉴别,必须从化学性质去考虑。
Substance identification is one of the common questions in chemistry exams. It is mainly based on the different properties of several substances - to find out what they are. Now we will talk about common types of problems and solutions with examples. 1 Optional reagent identification questions This type of question is generally analyzed first for the composition, type and characteristics of a given substance. The appropriate reagents are grouped according to their commonality, and then they are identified individually by their individuality. Example 1 Four bottles of colorless solution. They are potassium chloride, sodium carbonate, potassium nitrate and potassium sulfate. How to identify them? Analysis: Since these four solutions are colorless and transparent solutions, they cannot be identified by physical properties. Consider chemical properties.