问题 填空题

(6分)为防止碘缺乏病,通常在食盐中添加少量碘酸钾(KIO3),碘酸钾和碘化钾在酸性溶液中能发生下列反应。请配平化学方程式,用双线桥标出电子转移的方向与数目。

□KI+□KIO3+□H2SO4——□I2+□K2SO4+□H2O

此反应中,氧化剂是          ,还原剂是         

答案

(6分)配平化学方程式,用双线桥标出电子转移的方向与数目。

氧化剂: KIO3    还原剂:   KI      配平2分 双线桥2分 填空各1分

KI中碘元素从-1价变为0价,失去一个电子,为还原剂;KIO3中碘元素从+5价变为0价,得到5个电子,为氧化剂,根据得失电子数相等,KI系数为5,KIO3系数为1,I2系数为3,最后根据钾元素和氢元素守恒,配平

阅读理解

If a person tells you that something is “the real McCoy”,he is telling you it is the real thing,not a copy or replacement.There is nothing false about “the real McCoy”.It is the best that can be found.

There are different ideas on how the expression came into common use.Perhaps the most popular story is about a famous boxer,Charles Kid McCoy,a one-time world famous welter-weigh champion.One day,McCoy was having a drink in a bar with a lady friend.A man came up and began to talk to her.He was not a nice man.

McCoy wanted no trouble.He asked the man to leave.He said.“I'm Kid McCoy.”McCoy thought his name was so well-known that he didn’t need to say more.But the man did not believe him.“Oh,yeah?” he said.“Well,if you are Kid McCoy,then I am George Washington!” And he continued to speak to the prize-fighter’s friend in all unpleasant way.

McCoy hit the man with a fist-not hard-actually it was really a light touch.But the man fell to the ground,unconscious.Ten minutes later,when he came to sense,he called out. “That was the real McCoy!” And so,as told by kid McCoy,that was how the expression “the real McCoy” got started.

There are other versions,however.One is that the expression goes back to the days of prohibition(禁止)when it was illegal in the United States to sell whiskey.Although whiskey was against the law,many sold it.And many sold bad whiskey.They were not afraid to do so,because there was so little that anybody could do about it.Buying whiskey,good or had,was as illegal as selling it.

But there was one whiskey dealer who was honest.His name was McCoy.He refused to sell bad whiskey.He sold  only the best imported whiskey.His product became recognized as the best.It was called “the real McCoy”.

The expression survived prohibition days and soon became a general term.One way or another,no matter how the expression began,“the real McCoy” is an expression that everyone understands.It means the one and only—the best one.They are indeed words of special praise.

小题1:What is the main idea of the first paragraph?

A.It is about the exact meaning of the version.

B.It tells how a person gets his name.

C.It shows how to tell the real from the false.

D.It explains how to find the best.小题2:In the third paragraph,“the prize-fighter” refers to______.

A.a champion

B.George Washington

C.a fellow

D.McCoy小题3:Which of the following is TRUE about the days prohibition?

A.A national law forbade the sale of alcoholic drinks.

B.Bad whiskey was not allowed to sell.

C.People at that time preferred nothing but whiskey.

D.The days of prohibition resulted in MeCoy’s selling wine.小题4:What is the main idea of the whole passage?

A.The story of a famous boxer.

B.The general use of the version.

C.The expression and its story.

D.The friendship between an athlete and a seller.

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