问题 填空题

现有A、B、C、D、E五种化合物,它们的水溶液相互反应关系如下:

①A+B→C+H2O   ②C+H2SO4→D↓+A   ③E+AgNO3→AgC1↓+C

(1)试确定A、B、E的化学式:A______;B______;E______.

(2)写出②的化学方程式:______.

答案

(1)由反应③E+AgNO3→AgCl+C,可判断物质E为氯化物、物质C为硝酸或硝酸盐;由反应②C+H2SO4→D↓+A,可明确物质C为硝酸盐且能与硫酸反应的硝酸盐应为硝酸钡,因此物质A、D分别为硫酸钡和硝酸;由反应①A+B→C+H2O,则物质A可确定为硝酸、物质B为氢氧化钡;反过来再由反应可判断物质D为硫酸钡、E为氯化钡;

(2)由(1)可知C为硝酸钡,D为硫酸钡,A为硝酸,反应②的化学方程式为Ba(NO32+H2SO4=BaSO4↓+2HNO3

故答案为:(1)HNO3、Ba(OH)2、BaCl2

(2)Ba(NO32+H2SO4=BaSO4↓+2HNO3

阅读理解

Foolish(silly) Freddie lived in a small village. The people of the village laughed at him. They liked to show visitors how silly Freddie was. They thought this was a funny thing to do.

One day, a visitor came to the village.

"Watch this", a villager said, and called to Freddie. "Come and play a game, Freddie, " he shouted. Freddie walked slowly towards him, a silly smile on his face.

"Look! Freddie, "the villager said, "I’ve got something for you." He showed Freddie a dollar coin and a much larger 50-cent coin."Which would you like?" he asked Freddie.

Freddie took the 50-cent coin at once.

The villager laughed."See how foolish he is," he said."He always does that. He’s too silly to learn anything." He walked away, leaving Freddie with the visitor.

The visitor felt sorry for Freddie and said to him, "Although the 50-cent coin is bigger than the$1 coin, the$1 coin is worth(值) much more.Two times as much."

"I know that," Freddie said."But once I take the$1coin, they’ll stop playing the game."

小题1:根据第一段The people of the village laughed at him. They liked to show visitors how silly Freddie was.描述,可知选D

小题2:根据第一段They liked to show visitors how silly Freddie was. 描述,可知选A

小题3:根据最后一段The visitor felt sorry for Freddie and said to him, "Although the 50-cent coin is bigger than the$1 coin, the$1 coin is worth(值) much more.描述,可知他认为弗雷迪不知道这些硬币的价值.故选D

小题4:根据短文最后一句话"I know that," Freddie said."But once I take the$1coin, they’ll stop playing the game."可知弗雷迪这样做只是为了让人们不断地给他钱,故选C,他其实很聪明.

小题5:这篇短文主要描述了一个被村民们认为很傻的人,但是实际上这个人很聪明.故选B,foolish用引号括起来,表示相反的含义.

小题6:People laughed at Freddie because__________.

A.he often made up jokes

B.he didn’t like money

C.he looked very funny

D.they thought he was a fool小题7:The villagers wanted to show the visitors___________.

A.how silly Freddie was

B.how clever Freddie was

C.How kind people were to Freddie

D.that Freddie had much money小题8:The visitor felt sorry for Freddie because he though_________.

A.Freddie did not know money was useful

B.the villager was not kind enough to the boy

C.Freddie did not get along well with the villagers

D.Freddie did not know the dollar coin was worth more小题9:From the story we know that Freddie was__________.

A.poor

B.kind

C.clever

D.silly小题10:The best title for the passage should be __________.

A.Clever Villagers

B."Foolish" Freddie

C.Freddie and a Visitor

D.A Visitor and the Villagers

单项选择题