问题 选择题

a mol N2与a mol 14CO相比较,下列叙述正确的是

A.在同温同压下体积相等

B.在同温同压下密度相等

C.在标准状况下质量相等

D.质子数与中子数都相等

答案

答案:A

a mol N2与a mol 14CO,同温、同压、同体积同分子数;都是双原子分子,原子数也相等;a mol N2含质子14amol,中子14amol,质量数为28;a mol 14CO,含质子14amol,中子16amol,质量数30。

A.在同温同压下体积相等;B.在同温同压下,密度比等于摩尔质量比,密度不相等。

C.在标准状况下,物质的量相等,摩尔质量不等,质量不相等;

D.质子数与中子数不相等。

点评:考查阿伏伽德罗常数,和质子数、中子数、质量数相互关系。

阅读理解

阅读理解

     A young man once went to buy a pair of pants. When he got home, he went upstairs(上楼) to his

bedroom and put them on. He found that they were two inches(英寸) long.

     Then he came out of his room to see his mother and his two sisters. They were washing something

in the kitchen."These new pants are too long, they need to be shortened(缩短) about two inches.

Would one of you like to do this for me, please?" His mother and sisters were busy and none of them

said anything. The mother went upstairs after she had finished washing and shortened the pants two

inches. But she didn't tell her daughters about it.

     Later on, after supper, the elder sister remembered her brother's pants. So she went upstairs without

saying to anyone, and shortened the pants two inches.

     The younger sister went to the cinema, but when she came back, she also remembered what her

brother had said. So she ran upstairs, and took two inches off the legs of the new pants.

1. The new pants were __________.

A. too long for the young man

B. two inches long

C. six inches long

D. too short for the young man

2. The young man asked __________ to shorten his pants.

A. his mother and his two sisters

B. his mother and one of his sister

C. his mother

D. his mother or one of his two sisters

3. __________, his elder sister shorten his pants.

A. After supper

B. After the mother finished washing

C. After the young man went upstairs

D. After the younger sister went to the cinema

4. How many inches were the legs of the new pants shortened by at last?

A. Two.

B. Four.

C. Six.

D. Eight.

5. When the young man put on the pants, he would __________.

A. feel happy

B. be very sad

C. thank his family

D. be very excited

选择题