试题与答案

写出下列几种物质的化学符号 ①氧气______②水______③四氧化三铁___

来源：www.tikuol.com
题型：填空题

题目：

写出下列几种物质的化学符号

①氧气______②水______③四氧化三铁______④氮气______．

答案：

①氧气的化学式是O2．故填：O2．

②水中氢元素的化合价是+1，氧元素的化合价是-2，水的化学式是 H2O．故填：H2O．

③根据名称可知四氧化三铁的化学式是Fe3O4 ．故填：Fe3O4 ．

④氮气的化学式是N2．故填：N2．

考点：化学式的写法和意义化合价的求法
试题推荐
题型：阅读理解

阅读下面短文，从A-E五个句子中选出四个填人文中空缺处，使短文内容完整、正确。

       Jane is a bright young woman who comes from a rich and famous family. She goes to a good university.

But her family are so busy that they can hardly find time to be with her. 1.           So she spends a lot of time on

her QQ. She uses the name Linda on QQ and has made lots of friends.

       Last year Jane made a very special friend on QQ. 2.            He and Jane were both interested in rock

music. So it always took them hours to talk happily on QQ. Of course, they wanted to know more about each

other. 3.           He was a tall, good-looking young man with a big, happy smile. As time went by, they became

good friends. 

       4.           Jane asked him to let her go with him so that she could give David a surprise for his birthday. But

when David finally stood before her, she found that her special friend was a twelve-year-old boy named Jim!

A. David sent a picture of himself.

B. In fact, Jane is quite lonely.

C. One day Jane's father was going on a business trip to San Francisco.

D. His name was David and he lived in San Francisco.

E. Jane and David chatted on QQ happily and became good friends.

查看答案
微信公众账号搜索答案