问题 实验题

实验室制取乙酸丁酯的实验装置有以下甲、乙两种装置可供选用。

        

(甲)                    (乙)

制备乙酸丁酯所涉及的有关物质的物理性质见下表

 乙酸1-丁醇乙酸丁酯
熔点(℃)16.6-89.5-73.5
沸点(℃)117.9117126.3
密度(g/cm3)1.050.810.88
水溶性互溶可溶

(9g/100g水)

微溶
 

(1)制取乙酸丁酯的装置应选用___________(填“甲”或“乙”)。不选另一种装置的理由是______________________________________________________________。

(2)该实验生成物中除了主产物乙酸丁酯外,还可能生成的有机副产物有(写出结构简式)________________________________________________________________。

(3)酯化反应是一个可逆反应,为提高1-丁醇的利用率,写出两种可行的方法:

                       ;②                               

(4)从制备乙酸丁酯所得的混合物中分离、提纯乙酸丁酯时,需要经过多步操作,下列图示的操作中,肯定需要的化学操作是________________(选填答案编号)。

                     

A                  B                  C                  D

(5)有机物的分离操作中,经常需要使用分液漏斗等仪器。使用分液漏斗前必须_______________,某同学在进行分液操作时,若发现液体流不下来,其可能原因除分液漏斗活塞堵塞外,还有                 

答案

(1)乙。由于反应物乙酸、1-丁醇的沸点低于产物乙酸丁酯的沸点,若采用甲装置,会造成反应物的大量挥发。

(2)CH3CH2CH2CH2OCH2CH2CH2CH3     CH3CH2CH=CH2

(3)①增加乙酸浓度 ②减小生成物浓度(或移走生成物)。

(4)AB。

(5)检查是否漏水或堵塞,分液漏斗上口玻璃塞未打开(或漏斗内部未与大气相通,或玻璃塞上的凹槽未与漏斗口上的小孔对准)。

题目分析:(1)应该选择乙。由于反应物乙酸、1-丁醇的沸点低于产物乙酸丁酯的沸点,若采用甲装置,会造成反应物的大量挥发。

(2)在浓硫酸加热条件下会生成副产物醚和发生消去反应,故为CH3CH2CH2CH2OCH2CH2CH2CH3     和CH3CH2CH=CH2

(3)从化学平衡移动的角度分析可知①增加乙酸浓度 ②减小生成物浓度(或移走生成物)可以使平衡右移,有利于酯的生成;

(4)前者主要是萃取选A后者是分液选择B。

(5)检查是否漏水或堵塞,分液漏斗上口玻璃塞未打开(或漏斗内部未与大气相通,或玻璃塞上的凹槽未与漏斗口上的小孔对准)。

阅读理解

Your body, which has close relations with the food you eat, is the most important thing you own, so it needs proper treatment and proper nourishment(营养). The old saying “An apple a day keeps the doctor away. ” is not as silly as some people think. The body needs fruit and vegetables because they contain vitamin C. Many people take extra vitamins in pill form(丸剂), believing that these will make them healthy. But a good diet is made up of nourishing food and this gives all the vitamins you need. The body doesn’t need or use extra vitamins, so why waste money on them?

In the modern western world, many people are too busy to bother about eating properly. They throw away the good habits and throw anything into their stomachs, eating hurriedly and carelessly. The list of illnesses caused or made worse by bad eating habits is frightening.

小题1:From the first sentence we know that ________

A.all kinds of food you eat can be made into nourishment

B.your body is make up of the food you eat

C.what you eat has great effect on your health

D.the more you eat, the better you will feel小题2: How do you understand the old saying underlined in the passage?

A.Eating apples regularly brings lots of benefits to our health.

B.Doctors are no longer necessary if we eat an apple every day.

C.The apple is the best among all kinds of fruits.

D.An apple is a good way to cure illnesses.小题3: What can we conclude from the second paragraph?

A.Our bodies need food, or we can’t live.

B.Often eating apples is a good habit.

C.Taking extra vitamin pills is completely useless.

D.A good diet is of great importance for our health.小题4:In modern western countries, ________.

A.people don’t want to pay more attention to their eating

B.lots of people’s illnesses are caused or made worse by bad eating habits

C.people throw everything into their stomachs without digestion

D.people are only too busy to cook meals fro themselves小题5: If we want to keep healthy, we should ________ .

A.only eat an apple a day

B.eat properly

C.take as many vitamin pills as possible

D.throw everything into our stomachs slowly and carefully

单项选择题