问题 填空题

现有铁片、铜片、硝酸汞溶液和盐酸几种物质,预确定Fe、Cu、Hg、H的活动顺序,有如下三种方案:

A.Fe+HCl(将铁片投入盐酸中)  Hg(NO32+Fe(将铁片放入硝酸汞中) Cu+HCl(将铜片投入盐酸中)

B.Fe+HCl    Cu+HCl    Cu+Hg(NO32

C.Fe+HCl    Fe+Hg(NO32Cu+Hg(NO32

试评价这三种方案:

(1)最差的方案是 ______,理由是 ______;

(2)最好的方案是 ______,理由是 ______.

答案

根据各物质之间的反应,A方案可证明Fe>H,Fe>Hg,H>Cu,但Hg和H的顺序不能确定;B方案可证明Fe>H,H>Cu,Cu>Hg,即Fe>H>Cu>Hg;C方案可证明Fe>H,Fe>Hg,Cu>Hg,但Fe、Cu的活动性顺序不能确定,Cu、H的活动性顺序不能确定,Hg、H的活动性顺序不能确定;

故答案为:(1)C,Fe、Cu的活动性顺序不能确定,Cu、H的活动性顺序不能确定,Hg、H的活动性顺序不能确定

(2)B,能将Fe、H、Cu、Hg的活动性顺序确定下来

单项选择题
阅读理解

We could all see the Murray Uiver slowly moving back, but now all the water was gone . I couldn’t believe that the Murray had dried up, not one drop of water left.

One morning I went down to the river to try and catch some fish when I saw my boat high and dry (搁浅) on the bank . I rushed down the river and saw all mud—no water . The fish were just lying there, dying . I looked up to see if my friend was there . There was the nest but no eagle(鹰). I called out to her with my special whistle which I made out of steel.

Suddenly a big shadow came over to me and the eagle landed in her nest and gave her young the food she was out getting while I whistled. But then I suddenly noticed she was getting thinner and had a bit of sheep’s wool in the side of her talon(利爪). It was deadly quiet by the river bank , except for some sound from my dog. And also I couldn’t see one native animal or bird.

When I walked inside the kitchen. Mum and Dad had sad looks on their faces. “It’s time for us to move ,Son, because the river can no longer provide for(养活)us,” said Dad . I ran out of the kitchen door with tears in my eyes , and down to the river bank, to my favorite spot. I said goodbye to my eagle , crying.

When it was time to go , I saw my eagle fly up into the air with her chicks in her talons , going away to try and find another home ,just like us.

59. The passage is mainly about     

A. the author’s travel away from his hometown

B. the author’s feeling about being away from his friend

C. the author’s idea about being away from home

D. the author’s plan to leave for a new place

60. The underlined word “chicks” in the last paragraph refers to “     ”

A. the eagle’s children                B. the eagle’s food  

C. the eagle’s nest beside the river       D. the dog

61. According to the passage ,the eagle looked thinner most probably because      

A. the eagle had to feed its children     B. the eagle was seriously sick

C. the eagle lost many of his friends     D. there was not enough food for her

62. According to the passage , it can be inferred that       .

A. the eagle lived on the ground beside the author’s house

B. it was winter when the writer went away

C. the writer’s parents didn’t like to leave , either

D. some native animals and birds still lived in the place