问题 填空题

人类的生产和生活都离不开水.如图是自来水厂净水过程示意图.请根据示意图回答下列问题:

(1)自来水中Al3+超标有害健康,可能造成自来水中Al3+超标的操作是______;清水池中的水属于______(填“纯净物”或“混合物”).

(2)A池中通过______(填操作名称)除去水中的固体杂质.

(3)用氯气和亚氯酸钠(NaClO2)反应制取ClO2的反应方程式为:Cl2+2NaClO2═2ClO2+2X,X的化学式为______.

(4)自然界中有些井水受热后会产生一些沉淀,即通常所说的水垢,说明此井水可能为硬水,则此井水中含有______(填离子符号).

(5)为了实验的需要,把自来水进一步净化为蒸馏水,在实验室制取蒸馏水的蒸馏烧瓶里,通常要加入几粒沸石或碎瓷片,作用是______.

答案

(1)由于明矾的组成中含有氯元素,造成自来水中Al3+超标的操作可能是加入明矾;由于清水池中的水含有可溶性的物质,属于混合物.

(2)通过过滤除去水中的固体杂质.

(3)在Cl2+2NaClO2═2ClO2+2X方程式中左边有:氯原子、钠原子、氧原子的数目分别是4、2、2,在右边有氯原子、氧原子的数目分别是2、2、由质量守恒定律反应前后原子的种类及数目不变可知,X的化学式是NaCl.

(4)由于硬水是含有较多钙、镁离子化合物的水.所以,则此井水中含有Ca2+,Mg2+

(5)蒸馏时,通常要加入几粒沸石或碎瓷片,作用是防止暴沸.

故答为:(1)明矾;混合物.(2)过滤.(3)NaCl.(4)Ca2+,Mg2+.(5)防止暴沸.

阅读理解

Far from the land of Antarctica(南极洲), a huge shelf of ice meets the ocean. At the underside of the shelf there lives a small fish, the Antarctic cod.

For forty years scientists have been curious about that fish. How does it live where most fish would freeze to death? It must have some secret. The Antarctic is not a comfortable place to work and research has been slow. Now it seems we have an answer.

Research was begun by cutting holes in the ice and catching the fish. Scientists studied the fish’s blood and measured its freezing point.

The fish were taken from seawater that had a temperature of -1.88℃ and many tiny pieces of ice floating in it. The blood of the fish did not begin to freeze until its temperature was lowered to -2.05℃. That small difference is enough for the fish to live at the freezing temperature of the ice-salt mixture.

The scientists’ next research job was clear: Find out what in the fish’s blood kept it from freezing. Their search led to some really strange thing made up of a protein(蛋白质) never before seen in the blood of a fish. When it was removed, the blood froze at seawater temperature. When it was put back, the blood again had its antifreeze quality and a lowered freezing point.

Study showed that it is an unusual kind of protein. It has many small sugar molecules(分子) held in special positions within each big protein molecule. Because of its sugar content. It is called a glycoprotein. So it has come to be called the antifreeze fish glycoprotein. Or AFGP.

小题1:What is the text mainly about?

A.The terrible conditions in the Antarctic.

B.A special fish living in freezing waters.

C.The ice shelf around Antarctica.

D.Protection of the Antarctic cod.小题2:Why can the Antarctic cod live at the freezing temperature?

A.The seawater has a temperature of -1.88℃.

B.It loves to live in the ice-salt mixture.

C.A special protein keeps it from freezing.

D.Its blood has a temperature lower than -2.05℃.小题3:What does the underlined word “it” in Paragraph 5 refer to?

A.A type of ice-salt mixture.

B.A newly found protein.

C.Fish blood.

D.Sugar molecule.小题4:What does “glycol-” in the underlined word “glycoprotein” in the last paragraph mean?

A.sugar

B.ice

C.blood

D.molecule

单项选择题 B1型题