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如图所示：已知A、D、E、F是中学化学中常见的单质，B、C是氧化物，B是一种黑色有磁性的物质，C有两性．请填空：

（1）A是______．E是______．（填化学式）

（2）D跟水反应的化学方程式为______．

（3）C电解时，每生成1mol A，同时生成______mol E．

答案

B、C是氧化物，B是一种黑色有磁性的物质，应为Fe3O4，C有两性，应为Al2O3，则A、B之间的反应为铝热反应，所以A为Al，D为Fe，电解熔融的Al2O3生成Al和O2，则E为O2，Fe在高温下和水蒸气反应生成Fe3O4和H2，则F为H2，则

（1）由以上分析可知，A是Al，E是 O2，故答案为：Al；O2；

（2）Fe在高温下和水蒸气反应生成Fe3O4和H2，反应的化学方程式为3Fe+4H2O

 高温 
.
 
Fe3O4+4H2，

故答案为：3Fe+4H2O

 高温 
.
 
Fe3O4+4H2；

（3）根据反应2Al2O3

 通电 
.
 
4Al+3O2计算，n（O2）=
3
4
n（Al）=
3
4
×1mol=0.75mol，故答案为：0.75．

阅读理解

阅读理解。

    In our city there is a big zoo. There are lots of different animals in it. There are some scary tigers and lions

in it. They like eating meat. There also two big elephants and a baby elephant in it. Children like to ride them.

The elephants are very kind and friendly. They eat much grass and bananas.

    In the zoo, we can also see different kinds of bears-brown bears, black bears and white bears. They are all

slow and clumsy.

    Do you like the pandas? There's only one in the zoo. Her name is Fangfang. She is very cute. She likes

eating bamboo a lot. She's very interesting and lovely.

1. ______ are lovely and interesting. [ ]

A. Tigers

B. Elephants

C. Bears

D. Pandas

2. How many elephants are there in the zoo? [ ]

A. One.

B. Two.

C. Three.

D. Four.

3. There aren't ______ bears in the zoo. [ ]

A. black

B. grey

C. brown

D. white

4. Elephants eat ______. [ ]

A. grass and bananas

B. meat and oranges

C. bamboo and cakes

D. grass and cakes

5. Which of the following is NOT true? [ ]

A. Children like to ride the elephants in the zoo.

B. The elephants are very friendly to people.

C. There are two pandas in the zoo.

D. Lions and tigers are scary.

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单项选择题

在金融期货交易中，为适应人们控制股市风险而产生，并以现金结算的是( )。

A．外汇期货
B．利率期货
C．股指期货
D．黄金期货
查看答案