问题 选择题

某同学欲用实验证明铁、铜、汞的化学活动性顺序,他利用了铁片、铜片、硝酸汞[化学式:Hg(NO32]溶液和稀盐酸四种物质,设计了下列四组实验方案,其中可行的是(  )

A.①Cu+HCl    ②Fe+Hg(NO32   ③Cu+Hg(NO32

B.①Fe+HCl    ②Cu+HCl        ③Fe+Hg(NO32

C.①Fe+HCl    ②Fe+Hg(NO32    ③Cu+Hg(NO32

D.①Fe+HCl    ②Cu+HCl        ③Cu+Hg(NO32

答案

A、铜与盐酸不能反应,说明了活动性铜<氢;铁与硝酸汞反应置换出汞,说明活动性铁>汞;铜与硝酸汞反应置换出汞,说明活动性铜>汞;方案没有确定铁与铜的活动性关系;故A错误;

B、铁与盐酸混合能产生氢气,说明铁>氢,铜与盐酸混合不反应,说明氢>铜,铁与硝酸汞混合,能置换出汞,说明铁>汞,无法证明铜与汞的顺序,故B错误;

C、铁与盐酸混合能产生氢气,说明铁>氢,铁与硝酸汞混合,能置换出汞,说明铁>汞,铜与硝酸汞混合能置换出汞,说明铜>汞,无法证明铜与铁的顺序,故C错误;

D、铁与盐酸混合能产生氢气,说明铁>氢,铜与盐酸混合不反应,说明氢>铜,铜与硝酸汞混合能置换出汞,说明铜>汞,故D正确.

故选D.

阅读理解

阅读理解

    Frankly,I appreciate myself very much.Yes,I admit I'm in many aspects not as good as other people,but

I don't think I'm always not good.When I find what I've done or written is okay,I'll remain pleased with my

self for quite a few days,and if I receive praise for it,I'll even become so excited as to add a few words to

reward myself.

    True,I'm not modest at all.People may call me conceited (自负的).But I think otherwise.

    I appreciate other people.I appreciate anything good.Isn't it unfair to forget appreciating myself while

appreciating others?

    We Chinese generally tend to be modest,and we take pride in being so.For example,a Chinese man will

call his own wife zhuojing,meaning"my humble wife",and his own writings zhuozuo,meaning"my poor

writings".But if you call his wife a "rustic (乡村的) woman" or his writings"trash",he would,I'm sure,

declare he would make a clean break with you angrily.As a matter of fact,there is probably no difference

at all between what is said by him and you.

   I don't think it's wrong of you to freely praise yourself if you're really worthy of praise.As we know,there

is an old Chinese saying disparaging (蔑视) a melon seller,named Lao Wang,who keeps praising his own

goods.Well,why can't he praise his melons if they are really sweet and juicy?

    Lao Wang sells melons for a living.How could he carry on business if he,by imitating the affectations

(装模作样) of us intellectuals,were to show false modesty about his melons?He would sure enough die of

starvation.

     Selfappreciation is therefore a key to professional dedication and enjoyment of work.Needless to say,

the same is true of those who make a living with their pen.One will lose confidence in writing when he stops

admiring his own essays.

1.We know from the first three paragraphs that the author________.

A.is modest in some way

B.is pleased to be a good writer

C.is too conceited

D.thinks it unfair to appreciate others

2.What do we know about the author's attitude towards Chinese modesty according to Paragraph 4?

A.Supportive.  

B.Negative.

C.Neutral.  

D.Careless.

3.The author mentions the example of Lao Wang to prove that______.

A.Lao Wang is very proud of himself

B.melon sellers should praise their goods

C.reasonable selfappreciation is good

D.writers should learn from Lao Wang

4.The purpose of the passage is to encourage readers to be________.

A.modest  

B.considerate

C.respectful  

D.confident

单项选择题 B1型题