问题 填空题

以下是原水处理成自来水的工艺流程示意图。 

(1)原水中含Ca2+、Mg2+、HCO3-、Cl-等,加入石灰后生成Ca(OH)2,进而发生若干复分解反应,写出其中一个离子方程式____。

(2)凝聚剂除去悬浮固体颗粒的过程___(填写编号,多选倒扣分)。

①只是物理过程②只是化学过程 ③是物理和化学过程

FeSO4·7H2O是常用的凝聚剂,它在水中最终生成____沉淀。

(3)通入CO2的目的是____和____。

(4)气体A的作用是____。这种作用是基于气体A和水反应生成的产物具有____性。

(5)下列物质中___可以作为气体A的代用品(填写编号,多选倒扣分)。

①Ca(ClO)2 ②浓氨水③Na2 FeO4 ④SO2

答案

(1)Ca2+ +HCO3-+OH-=CaCO3↓+H2O或 Mg2+ +2OH-=Mg(OH)2↓或Mg2+ +2HCO3- +2Ca2+ +4OH-=Mg(OH)2↓+2CaCO3↓ +2H2O

(2)③ ;胶状Fe(OH)3

(3)除去Ca2+ ;调节pH

(4)杀菌消毒 ;强氧化

(5)①③

阅读理解

阅读表达。

阅读下面的短文,请根据短文后的要求答题。 (注意字数要求)

      A punctual person is in the habit of doing a thing at the proper time and is never late in keeping an

appointment.

     The unpunctual man, on one hand, never does what he has to do at the proper time. He is always in a hurry

and in the end loses both time and his good name. A lost thing may be found again, but lost time can never be

regained. Time is more valuable than material things. In fact, time is life itself. The unpunctual man is for ever

wasting and mismanaging his most valuable asset as well as other's. The unpunctual person is always

complaining that he finds no time to answer letters, or return calls or keep appointments promptly. But the

man who really has a great deal to do is very careful of his time and seldom complains of want of it. He knows

that he can not get through his huge amount of work unless he faithfully keeps every piece of work when it has

to be attended to.

     Failure to be punctual in keeping one's appointments is the sign of disrespect towards others. If a person is

invited to dinner and arrives later than the appointed time, he keeps all the other guests waiting for him; Usually

this will be regarded as a great disrespect to the host and all other guests present.

     Unpunctuality, moreover, is very harmful when it comes to do one's duty, whether public or' private,

Imagine how it would be if those who are put in charge of important tasks failed to be at their proper place at

the appointed time. A man who is known to be habitually unpunctual is never trusted by his friends or fellow

men.

1. What does the author think is the main difference between a punctual person and an unpunctual

    person? (No more than 20 words)

_____________________________________________________________________________________

2. According to the passage, the main reason that a person is always unpunctual is that

   (No more than! 0 words)

_____________________________________________________________________________________

3. What is the meaning of the underlined word "asset" in Paragraph2? (no more than 5 words)

_____________________________________________________________________________________

4. According to the third paragraph, when you are invited to dinner, what should you do?

   (No more than 10 words)

_____________________________________________________________________________________

5. Do you agree that unpunctuality does harm? Give your reason. (No more than 20 words)

_____________________________________________________________________________________

单项选择题