题干

某同学在实验室进行了碳还原氧化铜的实验,实验步骤如表:

实验装置

实验步骤

分析

①检验装置气密性

②把木炭和氧化铜的混合物放入试管,如左图所示连接实验装置

装置中存在的问题是____

③改进装置后,点燃酒精喷灯开始实验

装置B的作用是____

④反应结束时,先将导管从装置B中撤出,再停止加热

目的是____

⑤待试管冷却后将剩余固体M倒入烧杯,加入足量稀硫酸,过滤

得到蓝色滤液

滤渣为红色和黑色固体混合物

实验反思:剩余固体M中一定含有CuO、碳和____.混合物中仍含有氧化铜的原因可能是碳和氧化铜没有完全反应就停止了加热,或者还可能的原因是____

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答案(点此获取答案解析)

B\u8bd5\u7ba1\u5904\u4e0d\u5e94\u8be5\u6709\u6a61\u76ae\u585e,\u68c0\u9a8c\u4ea7\u7269\u662f\u5426\u6709\u4e8c\u6c27\u5316\u78b3,\u9632\u6b62\u6db2\u4f53\u5012\u6d41\u5f15\u8d77\u8bd5\u7ba1\u70b8\u88c2,\u94dc,\u4ece\u8bd5\u7ba1B\u4e2d\u64a4\u51f

同类题2

阅读理解

A Book Review—The Snake-Stone by Berlie Doherty

    The setting: Urban England (the cities), but also rural England (the countryside) including remote English villages.

    The theme: The main theme is a teenage search of self-discovery, in this case the search for a mother from whom the hero was separated at an early age. Its other concerns are love, getting on with others, being persistent and courageous and trying to deal with doubts, troubles and worries. As the book moves to a close, James' swimming coach says to him: “You are not like a kid obeying instructions any more. You are diving like a young man who knows where he is going.”

    The characters: James is the hero of the story. He is a championship diver, and has a comfortable life with his foster parents (养父母). Yet he also has the qualities to take him on a long journey to find his birth mother. The other characters in The Snake-Stone, James' parents, his diving instructor, best friend, the villagers, people he meets on his journey, are pictured realistically.

    The turning point: The turning point in the story comes while James' foster parents are away in London, and he wonders about the identity of his birth mother. The only clue he has is a fossil, “the snake stone” which she left behind along with a note on which she had written: “Take good care of Sammie. It was written on a torn envelope with parts of an address still there.

    The journey: Instead of going to London, James decides to find his birth mother. With help from his geography teacher, James sets out for the remote country village where his mother might be found. James has painful, challenging, but also humorous and happy travels. The mother he finally meets, Anne, has a minor yet powerful voice in the novel. He comes to understand why she left him at a stranger's door fifteen years before. Although the meeting is not long, it leaves him with a feeling of completeness. As a journey of self-discovery The Snake-Stone also provides its readers with a happy ending. Its hero says, on returning to his foster parents, “I was home.”