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不少初学化学的同学反映,氧化—还原反应式的配平不好掌握。分析其原因:一是一些同学对“基本的”氧化—还原反应式配平还不甚了解的时候,盲目“拔高”;也有的教师忽略学生认识能力,一下子深刻地讲了“全部”氧化—还原反应式配平的许多例子,学生来不及用自己认知结构同化所学新知识,囫囵吞枣。对氧化—还原反应方程式配平这一难点,是否可以这样引导、突破呢?反应实质参加反应的原子间的电子转移。(包括电子得失和电子对的偏移)。配平原则化合价升高总数=化合价降低总数(失电子总数=得电子总数)解题步骤1.正确写出发生氧化—还原变化的反应式;2.列出发生氧化-还原的元素的正负化合价;3.求化合价升高和降低数的最小公倍数,
Many beginner chemistry students report that the oxidation-reduction reaction trim is not well understood. Analysis of the reasons: First, some students do not understand the “basic” oxidation - reduction reaction trimming, blindly “pulling up”; and some teachers ignore students’ cognitive ability, all of a sudden talked about “all” oxidation - Many examples of reduction-response trimming have prevented students from using their cognitive structures to assimilate new knowledge they learned. The difficulty in balancing the oxidation-reduction equation is whether it can be guided and broken through. The reaction essentially participates in the interatomic electron transfer of the reaction. (Including the offset of electron gain and loss and electron pair). Balanced principle Total valence increase = total reduction in valence (total number of lost electrons = total number of electrons) Problem solving step 1. Correctly write out the reaction equation in which oxidation-reduction changes occur; 2. List the positive and negative valences of elements in oxidation-reduction 3. The minimum common multiple of increasing and decreasing the number