问题 选择题

下列离子或分子组中能大量共存,且满足相应要求的是

选项离子或分子要求
AK、NO3-、Cl、HSc(K) > c(Cl)
BFe3、MnO4、SO32-、Cl滴加盐酸立即有气体产生
CNH4+、Al3、SO42-、CH3COOH滴加NaOH溶液立即有气体产生
DNa、HCO3-、Ca2、I通CO2气体有沉淀产生
 

答案

答案:A

题目分析:离子间如果发生化学反应,则不能大量共存,反之是可以的。A、根据电荷守恒可知,因为氯离子浓度小于钾离子浓度,符合电荷守恒,且离子间可以大量共存,故A正确;B、由于Fe3+、MnO4均能够氧化SO32-,所以不能大量共存,故B错误;C、滴加NaOH会先和醋酸反应,再与Al3反应三醇氢氧化铝沉淀,最后与NH4+反应,故C错误;D、通CO2气体没有沉淀产生,故D不正确,答案选A。

单项选择题 A3/A4型题
阅读理解

阅读理解。

     I recently heard a story from Stephen Glenn about a famous research scientist who had made several very

important medical breakthroughs. He was being interviewed by a newspaper reporter who asked him why he

thought he was able to be so much more creative than the average person. What set him so far apart from

others?

     He responded that, in his opinion, it all came from an experience with his mother that occurred when he

was about two years old. He had been trying to remove a bottle of milk from the refrigerator when he lost his

grip on the slippery bottle and it fell, spilling its contents all over the kitchen floor-a real sea of milk!

     When his mother came into the kitchen, instead of yelling at him, giving him a lecture or punishing him,

she said, "Robert, what a great and wonderful mess you have made! I have rarely seen such a huge puddle

of milk. Well, the damage has already been done. Would you like to get down and play in the milk for a few

minutes before we clean it up?"

     Indeed, he did. After a few minutes, his mother said, "You know, Robert, whenever you make a mess like

this, eventually you have to clean it up and restore everything to its proper order. So, how would you like to

do that? We could use a sponge, a towel or a mop. Which do you prefer?" He chose the sponge and together

they cleaned up the spilled milk.

     His mother then said, "You know, what we have here is a failed experiment in how to effectively carry a

big milk bottle with two tiny hands. Let's go out in the back yard and fill the bottle with water and see if you

can discover a way to carry it without dropping it." The little boy learned that if he grasped the bottle at the

top near the lip with both hands, he could carry it without dropping it. What a wonderful lesson!

     This famous renowned scientist then remarked that it was at that moment that he knew he didn't need to

be afraid to make mistakes. Instead, he learned that mistakes were just opportunities for learning something

new, which is, after all, what scientific experiments are all about. Even if the experiment "doesn't work," we

usually learn something valuable from it.

1. The passage is intended to _____.

A. introduce the life story of a famous scientist

B. compare the different ways of family education

C. reveal the secret of the scientist's success

D. inspire the parents to improve their teaching methods

2. From the passage, we can know that Robert _____.

A. was very naughty when he was two

B. was so working hard as to succeed

C. owes a lot to his education from his mother

D. has made some great contributions to physics research

3. On seeing the spoiled milk, what did the mother do firstly?

A. She comforted his son.

B. She cleaned the floor.

C. She taught how to grasp the bottle.

D. She gave the boy a lecture.

4. Which of the following is the best according to the text?

A. It would be great if all the scientists can know the importance of the failed experiment.

B. It would be great if the experiment doesn't work at all.

C. It would be great if all parents would respond the way Robert's mother responded to him.

D. It would be great if we are more creative than the average person.