问题 填空题

(I)下列实验操作正确的是______

A.将无水乙醇加热至170℃时,可以制得乙烯

B.向溴乙烷中滴加硝酸酸化的AgNO3溶液,以检验其中的溴元素

C.用稀HNO3清洗做过银镜反应的试管;

D.苯酚、浓盐酸和福尔马林在沸水浴中加热可得酚醛树脂

E.乙醇、冰醋酸和2mol/L的硫酸混合物,加热制得乙酸乙酯

F.苯、浓溴水和铁粉混合,制取溴苯

G.用酒精洗涤盛放过苯酚的试管;H.用热NaOH溶液洗涤有油脂的试管;

(II)某实验小组用下列装置进行乙醇催化氧化的实验.

(1)实验过程中铜网出现红色和黑色交替的现象,请写出由黑色又变为红色的相应化学方程式放热______.在不断鼓入空气的情况下,熄灭酒精灯,反应仍能继续进行,说明该乙醇催化反应是______反应.

(2)反应进行一段时间后,干试管a中能收集到不同的物质,它们是______.集气瓶中收集到的气体的主要成分是______.

(3)若试管a中收集到的液体用紫色石蕊试纸检验,试纸显红色,说明液体中还含有______.要除去该物质,可现在混合液中加入______(填写字母).

a.氯化钠溶液     b.苯     c.碳酸氢钠溶液     d.四氯化碳

然后,再通过______(填试验操作名称)即可除去.

答案

(Ⅰ)A、乙醇在浓硫酸的作用下加热可以获得乙烯,体现浓硫酸的脱水性,故A错误;

B、溴乙烷中不含有自由移动的溴离子,和硝酸酸化的硝酸银不反应,应该向溴乙烷中加入氢氧化钠溶液,将溴原子转化为溴离子,再加入硝酸酸化的AgNO3溶液,如果出现淡黄色沉淀,证明含有溴元素,故B错误;

C、金属银可以和硝酸发生反应生成可溶性的硝酸银,可以用稀HNO3清洗做过银镜反应的试管,故C正确;

D、苯酚、福尔马林在浓盐酸的酸性环境下水浴中加热,可以发生反应得到酚醛树脂,故D正确;

E、用乙酸、乙醇以及浓硫酸加热可以制得乙酸乙酯,稀硫酸环境下不会发生此反应,故E错误;

F、苯、液溴和铁粉混合来获得溴苯,不能用溴水,必须用纯溴,故F错误;

G、苯酚易溶于乙醇中,可以用酒精洗涤盛放过苯酚的试管,故G正确;

H、油脂属于酯类,酯在氢氧化钠强碱性环境下可以水解为可溶性的羧酸钠盐和醇,用热NaOH溶液可以洗涤有油脂的试管,故H正确.

故选CDGH.

(Ⅱ)(1)乙醇的催化氧化实质是乙醇在催化剂铜的作用下被氧气氧化为醛的过程,开始时,金属铜被氧气氧化为氧化铜,金属铜红色变为黑色,然后氧化铜氧化乙醇为乙醛,CH3CH2OH+CuO

CH3CHO+Cu+H2O,反应是一个放热反应,在不断鼓入空气的情况下,熄灭酒精灯,反应仍能继续进行,

故答案为:CH3CH2OH+CuO

CH3CHO+Cu+H2O;放热;

(2)乙醇的催化氧化实验中的物质:乙醇、乙醛和水的沸点高低不同,在试管a中能收集这些不同的物质,空气的成分主要是氮气和氧气,氧气参加反应后剩余的主要是氮气,

故答案为:乙醛、乙醇、水;氮气;

(3)试管a中收集到的液体用紫色石蕊试纸检验,试纸显红色,说明液体中还含有具有酸性的物质乙酸,可能是乙醛继续氧化的结果,乙酸具有酸性,能使石蕊试液显示红色,可以向混合物中加入碳酸氢钠溶液,(该溶液和乙醇、乙醛等均不反应)然后蒸馏即可除去,故答案为:乙酸;c;蒸馏.

选择题
阅读理解

阅读理解。

     The World Health Organization estimates that more than 4 million people die each year from the

effects of smoking tobacco (烟草). That number is increasing.

     WHO officials expect 150 million people to die from tobacco use in the next twenty years. Seven in

ten of those deaths will be in developing countries. These numbers are frightening. Yet people around the world continue to smoke.

     It is not easy to stop smoking. However, doctors say you will live longer if you do stop smoking.

You will feel better and look better. You will also protect the health of family members who breathe in

your smoke.

     The American Cancer Society says there is not just one right way to stop smoking. It says that one

method or a unit of methods may be successful. These include attending self-help programs or following

directions in a book. The group says any way to stop smoking that is legal, moral and effective is worth

trying. This could include taking long walks or spending time in areas where smoking is not allowed.

Also, you could eat a small piece of fruit instead of having a cigarette.

     The American Cancer Society says the sooner smokers stop smoking, the more they reduce (减少)

their chances of getting cancer and other diseases. It says blood pressure returns to normal twenty

minutes after a smoker smoking the last cigarette. Carbon monoxide (CO) gas levels in the blood return

to normal after eight hours. In a day, the chances of a heart attack decrease. In a year, the risk of heart

disease is half that of a smoker.

1. Most people who will die from smoking are from ____.

A. big countries  

B. small countries  

C. developing countries

D. developed countries

2. The author may hold the attitude(态度)that ______.

A. people can easily give up smoking  

B. people will feel much better after giving up smoking

C. it is not necessary for people to give up smoking forever

D. it is hard to say whether it is good to give up smoking or not

3. According to the American Cancer Society, after smokers stop smoking, the quickest effect is

   that ________.

A. the chances of having a heart attack get smaller

B. blood pressure returns to normal

C. carbon monoxide gas levels in the blood return to normal

D. the risk of heart disease for a non-smoker is half that of a smoker

4. We can infer from the passage that________.

A. WTO officials say that a person will live longer if he / she stops smoking

B. the smoker can affect the health of his or her family members

C. following any way can help you stop smoking

D. no matter how hard you try it, it is worth doing that