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学生:您怎样知道在化学反应中,使用物质的多少? 教师:通常你使用的量是化学当量或接近于此量。假若,我们欲使10克的铝试样跟碘反应,你想想我们应该用多少碘呢? 学生:大约10克。教师:在质量上你使反应物相当,还要从原子方面来考虑。一个碘原子比一个铝原子大的多。它几乎是铝重的5倍。学生:那么,我想我们应该使用5倍于铝量的碘,50克,怎么样? 教师:倘若,每一个铝原子只能跟一个碘原子反应,那就是正确的。但是,不要忘记一个铝原子能够跟三个碘原子化合。学生:假若那样,我想我们应该使用三倍于50克的碘,大约是150克。唉!仅仅是
Student: How do you know the amount of substance used in a chemical reaction? Teacher: Usually the amount you use is the chemical equivalent or close to it. If we want to make 10 grams of aluminum sample react with iodine, do you think about how much iodine we should use? Student: About 10 grams. Teacher: You make the reactants quite similar in quality, but also from the aspect of the atom. An iodine atom is much larger than an aluminum atom. It is almost 5 times the weight of aluminum. Student: Well, I think we should use 5 times the amount of iodine, 50 grams of aluminum. How is it? Teacher: If every atom of aluminum reacts with only one iodine atom, that’s right. However, don’t forget that one aluminum atom can combine with three iodine atoms. Student: If so, I think we should use three times 50 grams of iodine, which is about 150 grams. Oh, it’s just