在初中化学奥赛题中 ,有一类题型是比较常见的 ,它涉及的几种物质在组成上有共同元素 ,考查的方式是直接或间接比较某元素的质量分数 ,这就是有关物质组成的计算型选择题。由于这类题并未要求我们通过计算求出精确答案 ,而只要我们通过比较选出合适的答案 ,当然就为我们找到解 In junior high school chemistry Olympic Games title, there is a class of questions is more common, it involves several substances in the composition of common elements, the way to examine is to directly or indirectly compare the quality of an element, which is the calculation of the composition of the relevant material Type multiple choice questions. Since such questions do not require us to calculate the exact answer by calculation, as long as we select the appropriate answer by comparison, we will of course find solutions for us.