问题 填空题

在有机物分子中,不同位置的氢原子的核磁共振谱中给出的特征峰值(信号)也不同,根据峰值(信号)可以确定有机物分子中氢原子的种类和数目.

(1)下列有机物分子中,其核磁共振氢谱图中只有1个峰的物质是______.

A.CH3-CH3     B.CH3COOH   C.CH3COOCH3  D.CH3COCH3

(2)化合物A和B的分子式都是C2H4Br2,A的核磁共振氢谱图如下所示,则A的结构简式为______.请预测B的核磁共振氢谱图上有______个峰.

答案

(1)核磁共振氢谱中只给出一种峰,说明该分子中的H原子都是等效的,只有1种H原子.

A、CH3CH3中6个H原子都是等效的,核磁共振氢谱中只给出一种峰,故A正确;

B、CH3COOH中甲基中的H原子与羧基中的H原子所处化学环境不同,CH3COOH有2种H原子,核磁共振氢谱中有2个峰,故B错误;

C、CH3COOCH3中甲基所处化学环境不同,甲基H原子不同,有2种H原子,核磁共振氢谱中有2个峰,故C错误;

D、CH3COCH3中2个甲基连在同一个羰基上,6个H原子都是等效的,核磁共振氢谱中只给出一种峰,故D正确;

故选AD;

(2)由A的核磁共振氢谱可知,分子中只有一种H原子,2个Br原子连接不同的碳原子,故A的结构简式为CH2BrCH2Br,B与A互为同分异构体,2个Br原子连接在同一碳原子上,B为CH3CHBr2,分子中有2中H原子,故核磁共振氢谱图有2个峰;

故答案为:CH2BrCH2Br;2.

完形填空

第三节回答问题(共3小题;每小题2分,满分6分)

阅读下面短文,根据第58至第60小题的具体要求,简要回答问题,并将答案转写到答题卡上。

In choosing a friend, one should be very careful. A good friend can help you study. But how do I know when I have found a good friend? I look for certain qualities(品质) of character, especially understanding, honesty and reliability(可靠).

Above all else, I look for understanding in a friend. A good friend tries to understand how another person is feeling. He puts himself in the other person’s place, and he tries to think of ways to be helpful. He is also a good listener.

At the same time, however, a good friend is honest. He does not look for faults(过错) in others. He notices their good points. In short, a friend will try to understand me and accept me.

Sometimes you will meet “fair weather friends”. They will be with you as long as you have money or luck, but when you are down, they will run away. So, I think another quality of a friend is reliability. I can always depend on(信赖) a good friend. If I need a favor, he will do his best to help me. If I am in trouble, he will not run away from me.

There is a fourth quality that makes a friend special. A special friend is someone with whom we can have fun. A good friend likes the same things I like. He likes to laugh with me. That is how we share in the joy of being friends. And I know that he is looking for the same quality in me.

When I meet someone who is reliable, honest, and understanding, I know I’ve found a friend!

58. According to the author, what good characters should a good friend have? (回答词数不超过9  

个)

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59. What’s the Chinese meaning of “fair weather friends”? (回答词数不超过4个)

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60.What will you do when your good friend is in trouble? (回答词数不超过8个)

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单项选择题