问题 填空题

自来水生产的流程示意图见下:

⑴ 混凝剂除去悬浮物质的过程              (填写序号)

①只是物理变化        ②只是化学变化     ③是物理和化学变化

FeSO4·7H2O是常用的混凝剂,它在水中最终生成                 沉淀。

⑵ 实验室过滤操作所用到的玻璃仪器是                                   

⑶ 我们有时感觉自来水“有漂白粉气味”是因为使用了氯气消毒,请写出有关的化学反应方程式                                               

下列物质中,               可以作为氯气的代用品。(填写序号)

① 臭氧     ②NH3(液)     ③K2FeO     ④SO2

⑷ 有些地区的天然水中含有较多的钙、镁离子。用离子交换树脂软化硬水时,先后把水通过分别装有      离子交换树脂和      离子交换树脂的离子交换柱。(填“阴”或“阳”)

⑸ 测定水中的溶解氧:量取20mL水样,迅速加入MnSO4和KOH混合溶液,再加入KI溶液,立即塞好塞子,振荡使完全反应。打开塞子,迅速加入适量硫酸溶液,此时有碘单质生成。用0.10mol/LNa2S2O3溶液滴定生成的碘,消耗了6.00mL Na2S2O3溶液。已知在碱性溶液中,氧气能迅速氧化Mn2+,生成物在酸性条件下可以将碘离子氧化为碘单质,本身重新还原为Mn2+

上述过程发生的反应可表示为:2Mn2++4OH+O2=2MnO(OH)2

MnO(OH)2+2I+4H+=I2+Mn2++3H2O     I2+2S2O32=2I+S4O62

求水中的溶解氧量(以mg·g-1为单位)

答案

⑴③(2分)  Fe(OH)3(2分)    ⑵ 漏斗 烧杯 玻璃棒(3分)

⑶ Cl2+H2O  HCl+HClO(2分)①③(2分)⑷ 阳 阴(2分)⑸ 12.0mg·g-1(2分)

题目分析:⑴FeSO4水解成Fe(OH)24 Fe(OH)2 +2 H2O+ O2="4" Fe(OH)3

⑶消毒利用氯气与水生成的HClO的氧化性, 臭氧和 K2FeO(Fe为+6价)有强氧化性。

⑷有阴阳离子的交换。

阅读理解

Laptop computers are popular all over the world. People use them on trains and airplanes, in airports and hotels. These laptops connect people to their workplace. In the United States today, laptops also connect students to their classrooms.

Westlake College in Virginia will start a laptop computer program that allows students to do schoolwork anywhere they want. Within five years, each of the 1500 students at the college will receive a laptop. The laptops are part of a $10 million computer program at Westlake, a 110-year-old college. The students with laptops will also have access to the Internet. In addition, they will be able to use e-mail to “speak” with their teachers, their classmates, and their families. however, the most important part of the laptop program is that students will be able to use computers without going to computer labs. They can work with it at home, in a fast-food restaurant or under the trees—anywhere at all!

Because of the many changes in computer technology, laptop use in higher education, such as colleges and universities, is workable. As laptops become more powerful, they become more similar to desktop computers. In addition, the portable computers can connect students to not only the Internet, but also libraries and other resources. State higher-education officials are studying how laptops can help students. State officials are also testing laptop programs at other universities, too.

At Westlake College, more than 60 percent of the staff use computers. The laptops will allow all teachers to use computers in their lessons. As one Westlake teacher said, “ Here we are in the middle of Virginia and we’re giving students a window on the world. They can see everything and do everything.”

小题1:The main purpose of the laptop program is to give each student a laptop to _______.

A.use for their schoolwork

B.access the Internet

C.work at home

D.connect them to libraries小题2:Why is the word “speak” in the second paragraph in quotation marks(引号)?

A.They don’t really talk.

B.They use the computer language.

C.Laptops have speakers.

D.None of the above reasons is correct.小题3:Which of the following is true about Westlake College?

A.All teachers use computers.

B.1500 students have laptops.

C.It is an old college in America.

D.Students there can do everything.小题4:A window on the world in the last paragraph means that students can _______.

A.attend lectures on information technology

B.travel around the world

C.get information from around the world

D.have free laptops小题5:What can we infer from the passage?

A.The program is successful.

B.The program is not workable.

C.The program is too expensive.

D.We don’t know the result yet.

填空题