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本文试通过一些具体的例子介绍在高中化学总复习中,培养学生解综合试题思路的若干具体方法。一、图示分析法:图示分析可以形象地反映出某些化学变化中量的变化关系,使学生便于分析和理解题意。例如:例一,室温时 A 体积由 CH_4 和 O_2 组成的混和气体引燃后冷到室温,体积改变为 B 体积。试确定原混和气体可能的组成。解:(1)写出有关的化学方程式CH_4+2O_2=CO_2+2H_2 O(液)(2)假设出过量的物质,如假设 O_2过量。(3)用□代表1个体积,用△代表过量的那部分 O_2。(4)图示分析:
This article tries to introduce some concrete methods for cultivating students to solve comprehensive test questions in the review of senior high school chemistry through some concrete examples. First, the graphical analysis method: graphic analysis can reflect the changes in the amount of certain chemical changes in the relationship, so that students can easily analyze and understand the meaning of the question. For example: Case 1. At room temperature, the volume of A is ignited by a mixture of CH_4 and O_2, cooled to room temperature, and the volume is changed to B volume. Try to determine the possible composition of the original mixed gas. Solution: (1) Write the relevant chemical equation CH_4+2O_2=CO_2+2H_2O (liquid) (2) Assuming excess material, assuming that O_2 is excessive. (3) Use □ to represent 1 volume and use △ to represent the excess O 2 . (4) Graphic analysis: