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问题 计算题

(1)某烃A 0.2mol在氧气中充分燃烧后，生成化合物B、C各1.2mol，则烃A的分子式是________。

（2）标准状况下，5.6 L甲烷和乙烯的混合气体，通过足量的溴水，使溴水的质量增加了4.2 g，求混合气体中甲烷的质量。

答案

(1)C6H12（2）混合气体中CH4的质量为1.6 g。

题目分析：(1)烃在氧气中完全燃烧的产物为H2O和CO2,又因为化合物B、C各1.2mol，所以该烃含有H2.4mol，含有C1.2mol，又因为该烃有0.2mol，所以烃A的分子式为C6H12；

（2）溴水的质量增加了4.2 g，即混合气体中含有乙烯4.2g，

所以乙烯的物质的量n=4.2/28=0.15mol，

甲烷的物质的量=5.6/2.4-0.15=0.1mol，

即甲烷的质量m=0.116=1.6g

点评：本题考查了有机物的基本计算，该题比较基础，难度不大。

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翻译题

完成句子

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2. Do tell me the ways you think of ________________(解决这个问题)as soon as possible.(solve)

3. Seldom ________________(他们玩)video games ever since they entered college.(play)

4. The two old sisters, ________________(被分隔了很长时间), held each other and burst into tears. (separate)

5. The professor could hardly find sufficient grounds on ________________(支撑)his argument in favor of the new theory.(base)

6. __________(暴露在阳光下)for too much time will do harm to one's skin.(expose)

7. At the thought of the progress in English __________(他已取得的), he will think of the strict and kind teacher.(progress)

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