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【简答题】
下图是实验室制备1,2—二溴乙烷并进行一系列相关实验的装置(加热及夹持设备已略)。 有关数据列表如下: 乙醇 1,2-二溴乙烷 乙醚 状态 无色液体 无色液体 无色液体 密度/g/cm 3 0.79 2.2 0.71 沸点/℃ 78.5 132 34.6 熔点/℃ 一l30 9 -1l6 请按要求回答下列问题: (1)A中药品为1:3的无水乙醇和浓硫酸混合液,写出制备乙烯的化学反应方程式:____________________________________________________________。 (2)气体发生装置使用连通滴液漏斗的原因_________________________________________。 (3)装置D中品红溶液的作用是_______________;同时B装置是,监测实验进行时E中是否发生堵塞,请写出堵塞时的现象_______________________________________。 (4)反应过程中应用冷水冷却装置E,其主要目的是___________________________;但又不能过度冷却(如用冰水),其原因是_____________________________________________。 (5)判断该制备反应已经结束的方法是__________________;结果学生发现反应结束时,无水乙醇消耗量大大超过理论值,其原因是_______________________________________。 (6)有学生提出,装置F中可改用足量的四氯化碳液体吸收多余的气体,判断改用四氯化碳液体是否可行______(填“是”或“否”),其原因是____________________________。
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参考答案:
举一反三
【单选题】听力原文: Recently. a man who was always i13 good health, spent a week in bed with severe flu. It was tile worse illness in his 1ife. The previous week, he and his wife separated. (30)It seems his unusual...
A.
How people fall ill.
B.
The influence of people's emotions on their health.
C.
A new method to cure breast cancer.
D.
Several ways to keep fit.
【单选题】当我们演讲时开头会产生( )效应,给人一个明显的第一印象
A.
优先
B.
吸引
C.
点播
D.
蝴蝶
【单选题】有齿突的椎骨是
A.
枢椎
B.
隆椎
C.
寰椎
D.
第一胸椎
E.
第六颈椎
【单选题】We may infer from the fourth paragraph that
A.
humans have been growing food crops more than ten thousand years.
B.
humans have learned how to produce biofuels for a long time.
C.
humans are just on the beginning of making biofuels.
D.
a cell wall includes four hemicellulose.
【单选题】听力原文: Recently, a man who was always in good health, spent a week in bed with severe flu. It was the worse illness in h is life. The previous Week, he and his wife separated. (30)It seems his unusual ...
A.
How people fall iii.
B.
The influence of people's emotions on their health.
C.
A new method to care breast cancer.
D.
Several ways to keep fit.
【判断题】提高劳动生产率可以增加单位时间里的使用价值和价值量。
A.
正确
B.
错误
【简答题】双极型三极管实现放大作用的重要参数是()。
【单选题】I saw a saw saw a saw.
A.
我看见一把锯子锯了一把锯子。
B.
我看见有人用锯子锯了锯子。
C.
我看见有人锯锯子。
【判断题】提高劳动生产率可以增加单位时间里的使用价值和价值量。
A.
正确
B.
错误
【单选题】有齿突的椎骨是
A.
第二胸椎
B.
第七颈椎
C.
第二颈椎
D.
第一颈椎
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