问题 阅读理解

     You may feel interested in students in other countries.Do they have so much homework? What do

they do in their free time? People did a survey in China,Japan,South Korea(韩国)and the US last year.

This is the result.

     Who studies the hardest?

     Chinese students spend the most time in studying.About half of Chinese students spend more than

two hours on their homework every day.

     Who sleeps most often in class?Japanese students fail asleep(睡着)in class more often,About 45%

of them sometimes doze off in class.It's 32% in South Korea,21%in the US and 5%in China.

     Who is the most distracted(分心的)?

     American students are the most active in class,but also the most distracted.64.2%of them chat with

friends in class. 46.9 of them eat something in class, and 38.9 of them send e-mails or read other books

in class.

     What do they do after school?

     In their free time, most Chinese students study or surf the Internet. Most American students hang out

with their friends. Most Japanese students do exercise, .Most South Korean students watch TV.

1.About _________of Chinese students spend more than 2 hours doing their homework every day.

A. 50%

B. 45%

C. 64.2%

D. 38.9%

2.According to the survey. _________ students sleep in class most often.

A. Chinese

B. Japanese

C. American

D. South Korea

3.The underlined phrase "doze off" mean _________in Chinese.

A. 听音乐

B. 玩游戏

C. 看小说

D. 打瞌睡

4.46.9%of American students_________ in their free time.

A. chat with friends

B. play games

C. eat something

D. send e-mails

5.Most American students, _________in their free time.

A. surf the Internet

B. hang out with friends

C. do sports

D. watch TV

答案

1-5   ABDCB

填空题

(14分)镍是一种十分重要的有色金属,但粗镍中一般含有Fe、Cu及难与酸、碱溶液反应的不溶性杂质而影响使用。现对粗镍进行提纯,具体的反应流程如下:

已知:

①2Ni2O3(黑色) 4NiO(暗绿色) + O2

物质CuSCu(OH)2Ni(OH)2NiS
Ksp8.8×10-362.2×10-205.48×10-163.2×10-19
 

根据信息回答: 

(1)28Ni在周期表中的第      周期;镍与稀硝酸反应的离子方程式为                                                      。实验表明镍的浸出率与温度有关,随着温度升高镍的浸出率增大,但当温度高于70℃ 时,镍的浸出率又降低,浸出渣中Ni(OH)2含量增大,其原因为                                            

(2)在溶液A的净化除杂中,首先将溶液A煮沸,调节PH=5.5,加热煮沸5min,静置一段时间后,过滤出Fe(OH)3。为了得到纯净的溶液B还需要加入以下物质      进行除杂(填正确答案标号)。

A、NaOH       B、Na2S        C、H2S         D、NH3﹒H2O

(3)已知以下三种物质的溶解度关系:NiC2O4>NiC2O4·H2O> NiC2O4·2H2O。则操作I、II名称是               ; D生成E的化学方程式为                       。

(4)1molE经上述流程得到纯镍,理论上参加反应的氢气为         mol。

(5)测定样品中的镍含量的基本思路是将Ni2+转化为沉淀,通过测量沉淀的质量进一步推算Ni含量。已知Ni2+能与CO32-,C2O42-、S2-等离子形成沉淀,但测定时常选用丁二酮肟(C4H8N2O2)作沉淀剂,生成分子式为C8H14N4O4Ni的鲜红色沉淀。从实验误差角度分析主要原因为:                                                  

单项选择题 B型题