问题 选择题

下列化学式书写规范的是                (    )

A.氧化镁mgO

B.氯化铝alCl3

C.五氧化二磷P2O5

D.一氧化碳CO

答案

答案:C

本题考查化学用语的意义及书写,解题关键是分清化学用语所表达的对象是分子、原子、离子还是化合价,才能在化学符号前或其它位置加上适当的计量数来完整地表达其意义,并能根据物质化学式的书写规则正确书写物质的化学式;注意化学式中字母的书写(大小写).

A、氧化镁mgO,元素符号的书写注意“一大二小”,改为“MgO”,故A错误;

B、元素符号的书写注意“一大二小”,则改为:氯化铝AlCl3,故B错误;

C、五氧化二磷P2O5,化学式书写规范,故C正确;

D、一氧化碳Co中,氧元素的元素符号书写错误,改为“CO”,故D错误.

故选C.

判断题
阅读理解

As the saying goes, nothing succeeds like success. People like to deal with a successful person. Why? You see there must be a reason why the person has achieved success. And most obviously it is because he is expert at what he is doing.

When given a chance, people would deal with the best. Naturally, the best way to produce a success is to do a lot of work. Your achievement and the fame it leads to will make it known to the public how good you really are. People will know this by your completed record or simply by recognizing it upon seeing you in action. Just as it becomes quite obvious that a man is a full-time tennis player when you see him play on the tennis court, it will become obvious that you are skilled in your work when people see you do your work. But many other image building ways are practical in producing a success image, as will be discussed in the following…

1. People like to deal with a successful person probably because _______.

A. they hope to know the secret of being successful

B. they don’t believe what he has achieved

C. they are eager to show respect to him

D. they feel uncertain if he is an expert

2. How can we know how good a person is at his work?

A. Work with him.

B. Study how he has achieved success.

C. Just look at him doing his work.

D. Watch him playing tennis on the tennis court.

3. The passage mainly tells that _____.

A. success image may come after success

B. people like to deal with a successful person

C. there are many image building ways

D. success image is or has been built in one’s work

(1—3 ACB)