问题 实验题

日常用的干电池构造、组成如图.某校化学活动小组正进行的研究性课题是《回收电池,变废为宝,保护环境——用锌皮制ZnSO4晶体》,请你和他们一道完成下列报告:

研究目的 _________

(一)用锌皮制ZnSO4晶体

实验用品: _________ _________

实验原理(写出化学方程式): _________

实验步骤(简述):

(1) _________

(2) _________

(3) _________

(二)在仅除去了可溶物而回收的干电池的固体物质中除了MnO2外,还含有什么物质,若用这样的MnO2作KClO3热分解制氧气的催化剂会发生什么后果?

答案

研究目的

(1)回收旧电池,了解废旧电池回收利用的方法,

(2)学习用废金属锌制取硫酸锌晶体的方法,练习蒸发结晶和过滤的操作方法;

(一)实验用品:

废旧电池的锌皮、稀硫酸、小烧杯、蒸发皿、玻璃棒、酒精灯、铁架台(带铁夹、铁圈)、漏斗、滤纸等;

实验原理:

Zn+H2SO4═ZnSO4+H2↑;

实验步骤:

(1)拨开废旧电池,将有关表皮、金属锌皮,石墨碳棒、金属铜帽、黑色糊状物等分类放置

(2)将锌皮投入盛有稀硫酸的小烧杯,搅拌,使之完全溶解,

(3)将上述溶液转入蒸发皿中加热蒸发至有大量晶体析出后,停止加热,趁热过滤,滤出的晶体用少量蒸馏水小心冲洗干净,即得硫酸锌晶体;

(二)因为还有一些碳单质留在混合物中,加热条件下氯酸钾分解生成的氧气,碳单质易剧烈燃烧,产生的热量和气体不能及时排出,就会引起爆炸.

阅读理解

The day when the jobs were handed out was one of the most exciting moments for all the children in the class. It took place during the first week of the term. Every kid was given a job for which they would be responsible for the rest of that school year.

Some jobs were more interesting than others, and the children were eager to be given one of the best ones. When giving them out, the teacher took into account which pupils had been most responsible during the previous year. During the previous year Rita had carried out the teacher’s instructions perfectly. All the children knew Rita would be given the best job.

But there was a big surprise. Each child received a normal job. But Rita’s job was very different. She was given a little box containing some sand and one ant. Though the teacher insisted that this ant was very special, Rita felt disappointed. Most of her classmates felt sorry for her. Even her father became very angry with the teacher and he encouraged Rita to pay no attention to this insignificant pet. However, Rita preferred to show the teacher her error by doing something special with that job of little interest.

Rita started investigating all about her little ant and gave the ant the best food, and it grew quite a bit bigger.

One day, a man, who looked very important, came into their classroom and declared, “Your class has been chosen to accompany me, this summer, on a journey to the tropical rain forest, where we will investigate all kinds of insects. Among all the schools of this region, your class has best cared for the little ant.”

That day the school was filled with joy and celebration. Everyone thanked Rita for having been so patient and responsible. And many children learnt that to be given the most important task you have to know how to be responsible even in what are the smallest tasks.

小题1:What did the teacher base his decision on when giving out jobs to the children?

A.Their characters and interests.

B.Their class performance during the previous year.

C.Their working performance during the previous year.

D.Their ability of managing their accounts during the previous year.小题2:What does the underlined sentence mean?

A.Each child got an important job.

B.Each child got an interesting job.

C.The perfect student got the job of everyone’s preference.

D.The most responsible student got the job of least interest.小题3:What is Rita’s attitude to her father’s suggestion?

A.Negative.

B.Uncertain.

C.Totally positive.

D.Acceptive.小题4:We can infer that the man who made the declaration is a _________.

A.hunter

B.director

C.biologist

D.principal小题5:What would be the best title for the passage?

A.Never complain about life.

B.Small tasks can lead to fortunes.

C.Men are best known by their friends.

D.Responsibility and intelligence bring good luck.

单项选择题 A2型题