问题 选择题

下列结合实验现象的反应方程式不正确的是

A.在放有金属钠的集气瓶中通入氯气,产生白烟 2Na+Cl2=2NaCl

B.向NaHCO3溶液中加入过量的澄清石灰水,出现白色沉淀

2HCO3-+Ca2++2OH-=CaCO3↓+CO32-+2H2O

C.在0.1 mol·L-1的K2Cr2O7溶液中滴加数滴1mol·L-1的NaOH溶液,溶液由橙色变成黄色

Cr2O72-+H2O 2CrO42-+2H+

D.压缩装有NO2气体的针筒,红棕色先变深后变浅但比原来还是要深2NO2N2O4

答案

答案:B

题目分析:钠与氯气生成氯化钠固体,产生白烟,A正确;NaHCO3溶液中加入过量的澄清石灰水,Ca2+和OH-个数比不是1:2,反应离子方程式为HCO3-+Ca2++OH-=CaCO3↓+H2O,B错误;向重铬酸钾溶液中氧化钠溶液,OH-与H+反应,平衡向右移动,溶液变黄,C正确;压缩装有二氧化氮气体的针筒,气体浓度增大,颜色加深,然后平衡向右移动,颜色变浅,但比原来深,D正确。

点评:将化学基本理论与化学方程式综合考查,思维容量大。

单项选择题
阅读理解

When you are talking to somebody at a party, do you focus entirely on the person you are speaking with or does your attention keep jumping around the room to all the other people there? General1y, if the person is someone you really want to talk to, you will focus on him. Most other people will only get about half of your attention.

You may think that this is OK, because if you don’t really want to talk to him, then what does it matter if you don’t give him your full attention? Consider two things. First, you may just not realize the importance of that conversation. If you are at a networking meeting and you hope to meet the CEO of Company X, but you end up talking to someone who has a low-level job at a different company, then you may let your attention wander (走神) as you speak to him. But maybe you don’t realize that this person has already met the CEO and could introduce you. Do you think he will do that if he feels you don’t really care about speaking to him? This doesn’t mean you need to spend the whole time talking to him. Five or ten minutes of real attentive (专心的) conversation can be worth 30 minutes to an hour of partial attention.

Second, whether you want to speak to someone is based on the situation. You can love your wife, but if she tries to talk to you while you are watching something you like on TV, where is your attention going? Make your own decision, but if you want her to feel valued, give her your 100% attention. The nice thing is that in many cases you can give her your attention for a few minutes and then return to what you were doing. You miss very little, she feels valued, and all is good.

60.The author’s opinion is made believable mainly by ________.

A. giving examples    B. using figures     C. asking questions       D. description

61.The second paragraph mainly tells you that ________.

A. you should focus on whoever you are talking to

B. you should be interested in everyone at a party

C. you can refuse to talk to someone you don’t like at a party

D. you should be patient with everyone at a party

62.A person who has a low-level job probably ________.

A. would like to talk to you                   B. is the one you’re looking for

C. wants to make friends with you         D. is well worth focusing on

63. What is the main idea of this passage?

A. Always be friendly to others at a party.

B. Improve your communication skills by focusing on others.

C. It is important for you to be active at a party. 

D. You should respect your wife at any time.