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所谓抽象就是不具体。化学高考题中常有用字母或文字表述已知条件和未知条件。这些文字和字母虽表示特定的数量关系、物质组成或化学变化,但多是“泛指”、“虚拟”,无实在之意,看上去捉摸不定,甚难理清思路,考生常感困惑。遇到这类题时可用具体数据或实例代入,以“实”代“空”,化“抽象”为具体,化“空拟”为实际,以达到化难为易的目的。这是本文所说的“实解”。 例1(93.26)将适量铁粉放入三氯化铁溶液中,完全反应后,溶液中的Fe~(+2)和F~(?+)浓度相等。则已反应的Fe~(3+)和未反应的Fe~(3+)的物质的量的比是
The so-called abstraction is not specific. Chemical examination questions often use letters or words to describe known conditions and unknown conditions. Although these words and letters represent specific quantitative relationships, material compositions, or chemical changes, they are mostly “generalized” or “virtual,” meaningless, and appear to be inconclusive. It is difficult to clarify ideas and candidates are often confused. When such problems are encountered, specific data or examples can be used to substitute them, and the “real” generation is replaced by “empty”, the “abstract” is specific, and the “empty plan” is actual, in order to achieve the goal of making things difficult. This is the “real solution” in this article. Example 1 (93.26) The appropriate amount of iron powder was placed in ferric chloride solution. After complete reaction, the concentrations of Fe~(+2) and F~(?+) in the solution were equal. The ratio of the amount of reacted Fe~(3+) and unreacted Fe~(3+) is