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在化学反应中,反应前后气体体积发生变化,或物质某些量的增减,与反应物量的减少、生成物量的增加有相应的关系,故可直接根据改变量进行化学计算,现举几例如下: 〔例1〕把一块重82克的极薄的纯净铁片浸入342克硫酸铜溶液,等反应完毕后(假定这时硫酸铜里的铜已全部析出)把附有铜的铁片从溶液中取出。洗净、干燥,再称重,得83.5克。问:①铁片上附有多少克铜?②原硫酸铜溶液的百分比浓度是多少? 解:设析出的铜为x克,参加反应的硫酸铜为
In a chemical reaction, the volume of gas changes before and after the reaction, or the increase or decrease of a certain amount of a substance, has a corresponding relationship with a decrease in the amount of a reactant and an increase in the amount of a product, so that the chemical calculation can be directly performed based on the amount of change. Next: [Example 1] An extremely thin pure iron piece weighing 82 grams was immersed in 342 g of a copper sulfate solution, and after the reaction was completed (assuming that copper in the copper sulfate had been completely precipitated at this time), the copper piece was affixed from Remove the solution. Wash, dry, and weigh again to give 83.5 g. Q: How many grams of copper are attached to the iron? 2 What is the percentage concentration of the original copper sulfate solution? Solution: Assuming that the precipitated copper is x grams, the participating copper sulfate is