问题 填空题

工业上采用的一种污水处理方法是:保持污水的pH在5.0~6.0之间,通过电解生成Fe(OH)3沉淀。Fe(OH)3有吸附性,可吸附污物而沉积下来,具有净化水的作用。某科研小组用此法处理污水,设计装置示意图,如图所示。

(1)实验时若污水中离子浓度较小,导电能力较差,无法使悬浮物形成浮渣。此时,应向污水中加入适量的________。

A.BaSO4

B.CH3CH2OH

C.Na2SO4

D.NaOH(2)电解池阳极发生了两个电极反应,其中一个反应生成一种无色气体,则阳极的电极反应式分别是:

①___________________________________________________;

②___________________________________________________。

(3)电极反应①和②的生成物反应得到Fe(OH)3沉淀的离子方程式是__________            ____。

(4)该燃料电池是以熔融碳酸盐为电解质,CH4为燃料,空气为氧化剂,稀土金属材料做电极。已知负极的电极反应是CH4 +4CO32-8e=5CO2+2H2O。则正极的电极反应是                       。为了使该燃料电池长时间稳定运行,电池的电解质组成应保持稳定,此电池工作时必须有部分A物质参加循环,则A物质的化学式是_________。

答案

(1)C(1分)

(2)Fe-2e=Fe2    4OH-4e=2H2O+O2↑(2分)

(3)4Fe2+10H2O+O2=4Fe(OH)3↓+8H或12Fe2+6H2O+3O2=4Fe(OH)3↓+8 Fe3(2分)

(4) O2+4e+2 CO2=2 CO32-(2分)    CO2(1分)

题目分析:(1)保持污水的pH在5.0~6.0之间,通过电解生成Fe(OH)3沉淀时,加入的使导电能力增强的电解质必须是可溶于水的、显中性的盐,故答案为:c;(2)活泼金属电极做电解池的阳极是,则电极本身放电,故答案为:Fe﹣2e=Fe2+;(3)二价铁离子具有还原性,能被氧气氧化到正三价,4Fe2++10H2O+O2=4Fe(OH)3↓+8H+,故答案为:4Fe2++10H2O+O2=4Fe(OH)3↓+8H+; (4)①料电池中,正极反应一定是氧气的电子的过程,该电池的电解质环境是熔融碳酸盐,所以电极反应为:O2+2CO2+4e=2CO32 (或2O2+4CO2+8e=4CO32),故答案为:O2+2CO2+4e=2CO32 (或2O2+4CO2+8e=4CO32); ②电池是以熔融碳酸盐为电解质,可以循环利用的物质只有二氧化碳,故答案为:CO2

阅读理解

阅读理解。

     Knowing the best way to study will help you to be a better student. By using your time properly, you

can do your homework more quickly. Learning to study is not difficult.

     The first thing to remember is that you must be willing to learn. It doesn't mean that you must always

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Knowing mathematics facts will be useful in your whole life. Knowing how to spell makes any kind of

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begin to work at it and understand it more clearly. Learning things can be fun if you are willing to work

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first find out the main parts and then recite the whole thing; check your homework after you finish it; never

forget the importance of review and preview.

    Don't try to spend a lot of time researching learning methods. There are many students who know many good learning methods but don't study well. They forget that the most useful learning method is to study

hard.

1. The main purpose of the article is______.

A. to prove that learning is not difficult      

B. to make the readers be interested in study

C. to tell the importance of self teaching    

D. to tell the students how to study well

2. The first thing to remember in studying is that ______.

A. you must like the subject              

B. you must follow the teacher

C. you must enjoy learning               

D. you must study hard

3. The following advice is given in the article EXCEPT______.

A. To put a pen, paper and books beside you before study.

B. To study at any possible time and place.

C. To review and preview

D. To pay attention to the most important things.

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5. From the passage, we can conclude that ______.

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D. Good methods, good results.

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