问题 选择题

由水电离出的c(OH-)=1×10-12 mol L-1的无色溶液中,一定能大量共存的离子组是

A.K+、Cr3+、Cl、NO3

B.Na+、Ca2+、Cl、HCO3

C.K+、Ba2+、Cl、NO3

D.K+、Na+、Cl、S2O32

答案

答案:C

题目分析:室温下,水电离出的c(OH)=1012 mol· L1的溶液pH=2或12。

A中Cr3+为绿色,不合题意;B中HCO3在pH=2或pH=12时不能大量共存;D中S2O32在pH=2的条件下不能大量共存(S2O32+2H+=S↓+SO2↑+H2O)。

点评:室温下,水电离出的c(OH)=1×1012 mol L-1的溶液可以是酸溶液或碱溶液。

填空题
选择题

Last week, my granddaughter started kindergarten,and ,as is conventional, I wished her every success ,But part of me didn’t.

I actually wanted her to fail in some ways because I believe that failure can be good for our learning process, Success is proving that you can do something that you already know you can do , First –time success is usually a fluke (侥幸),First-time failure ,by contrast,is expected ;it is the natural order of things Failure is how we learn.

In Africa they describe a good cook as “she who has broken many bots”,If you’ve spent enough time in the kitchen to break a lot of pots ,probably you know a lot about cooking ,I once had dinner with a group of cooks and they spent a lot of time comparing knife wounds and burn scars ,They Knew how much their failures gave them.

I earn my living by writing a daily newspaper column, Each week I am aware that one column I write lill be my sores , I don’t set out to write it ; I try my best every day. I have learned to cherish that column ,A good column usually means that I am discussing a familiar topic, writing in a style I am used to or saying the same things as someons else but in fancy way.

Ny younger daughter is a trapeze artist(杂技荡秋千演员),She spent three years putting together a show and she did it successfully for years ,There was no reason for her to change it-but she did anyway, She said she was no longer learning anything new and she was boued; and if she was bored ,there was no point in subjecting her body to all that stress

My granddaughter is a perfectionist She will feel her failures ,and I will want to comfort her, But I sill also ,I hope ,remind her of what she learned ,and how she can do better next time ,I hope I can tell her ,though ,that it’s not the end of the world ,Indeed,  with juck ,it is the beginning.

小题1:Why did the author want his granddaughter to fail?

A.Success is boring though beneficial

B.She would learn more from failure

C.It is impossible to do everything successfully

D.He wanted her to be strong enough to face hardships小题2:What’s the author’s attitude toward his daughter changing her show/

A.Negative

B.Worried

C.Positive

D.Excited小题3:The author develops the article mainly by        

A.giving examples

B.following the time order

C.comparing different opinions

D.analyxing cause and effect小题4:The writer talks about his own experience to show that        

A.we cannot depend on luck to live a good life

B.we shoule try every possible way to avoid failure

C.past failures prevented him from taking risks in writing

D.the thought of failure will make you work even harder小题5:Which of the following can be the best title of the text?

A.Learn from failure

B.How to be a good cook

C.My daughter and granddaughter

D.A good column makes a good writer