问题 选择题

下列实验操作中,正确的是 (    )

A.配制5%NaCl溶液时,将称量的NaCl放入烧杯中加计量的水搅拌溶解

B.配制1mol·L1NaOH溶液时,将溶解后的NaOH溶液立即注入容量瓶

C.配制0.1mol/L的H2SO4溶液时,将量取的浓H2SO4放入容量瓶中加水稀释

D.分液操作时,先将分液漏斗中的下层液体放出,然后再将上层液体放出

答案

答案:A

考查实验基本操作

A.正确

BC项:烧碱溶液或浓硫酸不能直接注入容量瓶,需要先在烧杯中溶解或稀释、冷凝后再移到容量瓶中

D项:分液操作时,先将分液漏斗中的下层液体从下口放出,然后再将上层液体自上口倒出

故答案为A

阅读理解

阅读理解。

     Once a group of 17-year-old schoolboys decided to break the world basketball marathon record (马拉

松记录). They wanted to play for ninety hours and that is to add six hours to the record. Each team has

nine players, with five at a time. The boys decided each person would play 21.5 hours and then rest for 2

hours. Then they started at 6 o'clock in the evening.

    The first night was very hard for the players. When it was their turn to rest, they were too excited to fall

asleep at once. After sleeping for a short time, they had to play again. On the second night, they fell asleep

as soon as they stopped. Some of them had trouble with their feet and hands, but the only serious problem

was a psychological (心理上的) one. Each boy was thinking: Why am I doing this? How can I play any longer?

    After the third night, The players knew they could finish the ninety hours. The basketball on the fourth

night was very slow. But in the final hours, the players got better. For the last few minutes, the players looked

as fresh as when they started. How happy everyone was!

1. In the story, there were ______ schoolboys playing basketball marathon.

A. 9

B. 14

C. 17

D. 18

2. Before this basketball marathon, the world record was ______.

A. 84 hours

B. 86 hours

C. 90 hours

D. 96 hours

3. The first night was hard for the players to fall asleep because ______.

A. they were too excited

B. they only slept for a short time

C. no one watched them play

D. it was very long

4. The word "fresh" in the sentence"…the players looked as fresh as when they started" means ______.

A. 新鲜的

B. 兴奋不已的

C. 精神饱满的

D. 伤痕累累的

5. Which of the following sentences is wrong?

A. Some of the boys were hurt when they played.

B. It was hard for the players to fall asleep at night.

C. The boys started playing at 6 o'clock in the evening.

D. In the end, the boys felt happy.

选择题