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一、转换法在某些由多种元素组成的化合物中,当某种元素的表观化合价(氧化数)为分数时,仍按常规方法配平难度很大,此时可将化合物的分子式进行变形转换,使之成为熟悉的形式,再进行配平。[例1]配平 Na_2S_x+NaClO+NaOH—Na_2SO_4+NaCl+H_2O。分析:Na_2S_x中 S 的表观化合价为-2/x 价,这种价态学生不能接受,也不便于配平。根据上述物质组成的特点,可将 Na_2S_x 变形为 Na_2S·S_(x-1),在 Na_2S 和 S_(x-1)中 S 的化合价分别为-2价和0价,电子转移分别是:
First, the conversion method In some compounds composed of multiple elements, when the apparent valence (oxidation number) of an element is a fraction, it is still very difficult to trim according to the conventional method, at this time the molecular formula of the compound can be deformed Convert it so that it becomes a familiar form and then trim it. [Example 1] Balance Na_2S_x+NaClO+NaOH-Na_2SO_4+NaCl+H_2O. Analysis: The apparent valence of S in Na_2S_x is -2/x, which is not acceptable for valence students and it is not easy to balance. According to the characteristics of the above composition, Na_2S_x can be transformed into Na_2S·S_(x-1). The valences of S in Na_2S and S_(x-1) are -2 and 0, respectively. The electron transfer is: