问题 推断题

有机化合物A~H的转换关系如下所示:

链烃A有支链且只有一个官能团,其相对分子质量在65~75之间,1 mol A完全燃烧消耗7 mol氧气,请回答下列问题:

(1)A的结构简式是        

(2)由F转化为G的化学方程式是                       

(3)G与金属钠反应能放出气体,由G转化为H的化学方程式是               

(4)①的反应类型是           ;③的反应类型是            

(5)链烃B是A的同分异构体,分子中的所有碳原子共平面,其催化氢化产物为正戊为烷,写出B任一可能的结构简式                               

(6)C也是A的一种同分异构体,它的一氯代物只有一种(不考虑立体异构,则C的结构简式为     

答案

+2NaOH→(CH3)CHCH(OH)CH2OH + 2NaBr

题目分析:(1)由H判断G中有5个碳,进而A中含有5个C,再看A能与H2加成,能与Br2加成,说明A中不饱和度至少为2。又根据1mol A燃烧,消耗7molO2可知,故A分子式为C5H8。再据题意A中只有一个官能团,且含有支链,可以确定A的结构简式如下:(CH32CHCCH,名称是3-甲基-1-丁炔。

(2)(CH32CHCCH与等物质的量的H2完全加成后得到E:(CH32CHCH=CH2。E再与Br2加成的反应生成卤代烃F,卤代烃F能在氢氧化钠溶液中发生水解反应生成醇。

(3)G与金属钠反应能放出气体,则根据以上分析可知,G是二元醇,和二元酸发生酯化反应。根据生成物H的结构简式可知,反应中生成2分子水,因此H是环酯。

(4)①③分别是加成反应而后取代反应。

(5)该问难度增大,考查了共轭二烯烃的共面问题,超纲!注意有的同学写CH2=CH-CH2-CH=CH2是不符合一定共面这个条件的,球棍模型为:;CH3CH=CH-CH=CH2(存在顺反异构)是共轭二烯烃,中间单键不能旋转可以满足;CH3CH2CCCH3可以满足,三键周围的四个碳原子是在同一条直线的,那另外那个碳原子无论在哪个位置都是和这4个碳共面的,因为一条直线和直线外一点确定一个平面。

(6)该问难度更大,超出一般学生的想象范围,其实在早几年的全国化学竞赛试题里已经考过,要抓住不饱和度为2,,一个三键不能满足1氯代物只有一种,同样两个双键也不能满足,一个环,一个双键也不能满足,因此只能是两个环,即5个碳只能是两个环共一个碳了。

点评:该题综合性强,难度大,特别是后2问,学生不易得分。该类试题需要注意的是结构—官能团—性质,这条主线一直是高考的主干题型,主要是以烃和烃的衍生物连续起来考查官能团的转化关系,涉及到具体的知识点有:通过计算确定分子式和结构简式,并对其命名;三键的加成,双键的加成,卤代烃的水解,二元醇与二元酸的酯化;方程式的书写,反应类型的书写,同分异构体的判断与书写。解答有机推断题时,学生应首先要认真审题,分析题意,从中分离出已知条件和推断内容,弄清被推断物和其他有机物的关系,以特征点作为解题突破口,结合信息和相关知识进行推理,排除干扰,作出正确推断。

阅读理解

阅读理解。

     People who have lost the ability to understand or use words due to brain damage are called aphasics (失语

症患者). Such patients can be extremely good at something else. From the changing expressions on speakers'

faces and the tones of their voices, they can tell lies from truths.

     Doctors studying the human brain have given a number of examples of this amazing power of aphasics.

Some have even compared this power to that of a dog with an ability to find out the drugs hidden in the

baggage.

     Recently, scientists carried out tests to see if all that was said about aphasics was true. They studied a mixed

group of people. Some were normal; others were aphasics. It was proved that the aphasics were far ahead of

the normal people in recognizing false speeches-in most cases, the normal people were fooled by words, but

the aphasics were not.

     Some years ago, Dr. Oliver Sacks wrote in his book about his experiences with aphasics. He mentioned a

particular case in a hospital. Some aphasics were watching the president giving a speech on TV. Since the

president had been an actor earlier, making a good speech was no problem for him. He was trying to put his

feelings into every word of his speech.

     But his way of speaking had the opposite effect on the patients. They didn't seem to believe him. Instead,

they burst into laughter. The aphasics knew that the president did not mean a word of what he was saying.

He was lying!

     Many doctors see aphasics as people who are not completely normal because they lack the ability to

understand words. However, according to Dr. Sacks, they are more gifted than normal people. Normal people

may get carried away by words. Aphasics seem to understand human expressions better, though they cannot

understand words.

1. What is so surprising about aphasics?

A. They can fool other people.

B. They can find out the hidden drugs.

C. They can understand language better.

D. They can tell whether people are lying.

2. How did the scientists study aphasics?

A. By asking them to watch TV together.

B. By organizing them into acting groups.

C. By comparing them with normal people.

D. By giving them chances to speak on TV.

3. What do we learn from this text?

A. What ones says reflects how one feels.

B. Aphasics have richer feelings than others.

C. Normal people often tell lies in their speeches.

D. People poor at one thing can be good at another.

单项选择题