问题 实验题

如图实验装置用于验证某些物质的性质.在试管A中装入足量的固体NaHCO3.试回答下列问题:

(1)在A试管内发生反应的化学方程式是_______________________________________________;

(2)B装置的作用是__________________________________________________;

(3)在双球干燥管内发生反应的化学方程式为___________________________________________;

(4)双球干燥管内观察到的实验现象是___    _____, 上述实验现象说明_________________ _;

(5)若将干燥管内的Na2O2换成Na2O,则双球干燥管内观察到的实验现象是______________________。

答案

(1)2NaHCO3Na2CO3+H2O+CO2↑ (1分)

(2)吸收气体中的水蒸气(干燥CO2)(1分)(3)2Na2O2+2CO2=2Na2CO3+O2(1分)

(4)淡黄色的Na2O2逐渐转变为白色粉末,点燃的蚊香燃烧更加剧烈(2分)

Na2O2能与CO2反应,生成白色粉末状物质和O2(2分) (5)点燃的蚊香逐渐熄灭(2分)

题目分析:(1)碳酸氢钠不稳定,受热易分解,反应的化学方程式为2NaHCO3Na2CO3+H2O+CO2↑。

(2)由于生成的CO2气体中含有水蒸气,所以浓硫酸的作用是吸收水蒸气,干燥CO2

(3)CO2能和过氧化钠反应生成碳酸钠和氧气,反应的化学方程式为2Na2O2+2CO2=2Na2CO3+O2

(4)CO2能和过氧化钠反应生成碳酸钠和氧气,所以实验现象是淡黄色的Na2O2逐渐转变为白色粉末,点燃的蚊香燃烧更加剧烈。

(5)由于氧化钠与CO2反应生成的是碳酸钠,得不到氧气,因此点燃的蚊香逐渐熄灭。

阅读理解

Three years ago I listened to a lecture on cognition (认知) that changed the way I think about intelligence. There are two types of cognition. The first is normal cognition: the ability to regain knowledge from memory. The second type of cognition is metacognition: the ability to know whether or not you know.

Does this affect intelligence? In traditional education, intelligence is measured by cognitive ability. Some people can easily produce everything they know on a test. But others are awarded with poor grades and considered inferior. But does this inability make them any less intelligent? If the question came up on a task, they could refer to a book or a quick Google search. In reality they’re just as effective as the people that ace a test. They just can’t prove it as easily.

Metacognition is more important to success than cognition. A person with poor cognitive ability, but great metacognitive ability might do poorly in school, but when faced with a challenge, they understand their abilities and take the best course of action. For example, when faced with a question, a person with strong metacognitive ability will deal with it like this. If he knows the answer, but can’t come up with it, he can always do a bit of research. If he knows for sure that he doesn’t know, then he can start educating himself. Because he’s aware of his ignorance, he doesn’t act with foolish confidence. These people might not seem intelligent at first glance, but because they know what they know, they make better decisions and learn the most important things.

However, people with great cognitive ability but poor metacognitive ability may be considered excellent at a young age for acing every test and getting great SAT scores. Unfortunately, they’ve been ruined by poor metacognition: they think they know everything but they really don’t. They are overconfident, fail to learn from mistakes, and don’t understand the slight differences of personal relationships, showing disregard for persons with lower cognitive ability. They may make the worst decisions.

The most important mental power is the ability to know what you don’t know. The recognition of a fault is the first step to improvement. Don’t try to hide a lack of knowledge. For intelligent people this is the toughest lesson to learn.

小题1:People with great cognitive ability tend to _________.

A.do well in tests

B.be considered inferior

C.be more effective than others

D.do research when faced with a task小题2:The underlined phrase “take the best course of action” probably means _________.

A.starting educating himself

B.taking action during the course

C.making the right decision

D.coming up with many ideas小题3:People with poor metacognition may not succeed because they_________.

A.lack basic moral values

B.have improper self-evaluation

C.fail to communicate with others

D.show little respect for others小题4:The author probably supports the idea that _________.

A.intelligence is measured by cognitive ability

B.cognition is the most important mental power

C.the toughest lesson is to distinguish the two types of cognition

D.the awareness of one’s ignorance contributes to one’s improvement

单项选择题