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离子方程式的书写是中学化学教学的重要内容之一,在《大纲》中明确要求“能正确书写离子方程式”。离子反应贯穿中学化学之始终,涉及面广,运用广泛。然而学生在学习过程中往往不能正确书写离子方程式,也不能对其判断正确与否。本文就离子方程式正误判断方法谈点拙见。一、判反应原理化学反应的发生有它内在的规律,书写首先要明确反应原理,遵循客观事实,切忌臆造化学方程式。例1:将金属钠投入到硫酸铜溶液中,离子方程式错写为:2Na﹢Cu2﹢﹦2Na﹢﹢Cu.错误的原因是只考虑了活泼的金属把不活泼的金属从它的盐溶液中置换出来这一反应规律,而忽略了活泼金属钠首先要与水反应。正确的书写是:
The writing of ion equation is one of the important contents of chemistry teaching in middle school. It is explicitly stated in the Outline that “the ion equation can be written correctly”. Ion reaction throughout the middle school chemistry has always involved a wide range of widely used. However, students often can not correctly write ion equation in the learning process, nor can they judge whether it is correct or not. This article on the positive and negative ion equation judgment method to talk about humble opinion. First, the principle of adjudication reaction The occurrence of chemical reactions have its inherent laws, writing must first clear reaction principle, follow the objective fact, should not be hypocritical chemical equation. Example 1: Metal sodium into copper sulfate solution, the ion equation is wrongly written as: 2Na + Cu2 + = 2Na ++ Cu. The reason for the error is that only consider the lively metal to the inactive metal from its salt solution Replacement of the reaction of the law, while ignoring the active metal sodium first reaction with water. The correct writing is: