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纵观近几年中考试题,经常出现“物质共存”、“离子共存”的试题.所谓的物质共存或离子共存,在初中阶段指的就是:构成物质的不同离子在溶液中能同时存在,相互之间不能发生反应.也就是在同一溶液中不同离子之间不能结合成沉淀或气体或水.通过对中考试题分析,常有以下几种题型,现举例说明.一、判断物质或离子能否共存例1(2010年南昌市)下列各物质能在溶液中共存的是
Throughout the mid-term exam questions in recent years, often appear The so-called material coexistence or ionic coexistence, refers to in the junior high school stage is: different ions constituting the material in solution can At the same time, can not react with each other, that is, in the same solution can not be combined into different ions in the precipitation or gas or water through the analysis of the test questions, often the following types of questions, are an example. Coexistence of substances or ions Example 1 (Nanchang 2010) The following substances can coexist in solution is