问题 实验题

某研究性学习小组采用温和水溶液法,以CuCl2·2H2O和H2C2O4·2H2O为原料合成新颖结构的草酸铜晶体。为进一步探究草酸铜晶体的性质,现将草酸铜晶体在一定条件下加热分解,对所得气体产物和红色固体产物进行实验和研究。

Ⅰ、用以下装置检验气体产物的成分。

(1)C装置的作用是检验          ,D装置的作用是检验           。(用化学式回答)

(2)用PdCl2溶液检验CO时发生反应的化学方程式为______________________________;

(3)D、E两装置位置能否互换?为什么?_____________________________________。

(4)若需测定气体产物的含量,则A装置能很好地降低实验误差,在实验中,至少有____次使用到A装置,分别起什么作用?_____________________________。

Ⅱ、对固体产物的成分进行探究

①提出合理假设:

假设1:红色固体为Cu ;

假设2:红色固体为Cu2O ;

假设3:              

②设计实验方案证明你的假设(不要在答题卡上作答)

③实验过程

根据②中方案进行实验在答题卡上按下表的格式写出实验步骤、预期现象与结论。

实验步骤预期现象与结论
步骤1: 
步骤2: 
…… 
 

答案

Ⅰ、(1)H2O(1分)、CO2 (1分)

(2) PdCl2  +  CO  +  H2O  =  Pd↓ +  CO2  +  2HCl (方程式书写完整2分)

(3)不能,若互换则E装置中可能产生的CO2对D装置中CO2的检验造成干扰。(其他合理答案也可,2分)

(4)2   (1分)

加热晶体前,通氮气可除去装置中的空气;加热晶体后,通氮气可把分解产生的气体产物全部赶出来。(其他合理答案也可,2分)

Ⅱ、①假设3:红色固体为Cu2O和Cu的混合物。(1分)

③实验过程(每空1分,先检验Cu2O、后检验Cu亦可)

实验步骤预期现象与结论
步骤1:取适量固体产物于试管中,加入足量浓氨水,充分振荡使其溶解若固体产物全部溶解,则假设2成立;若固体产物未全部溶解,则假设1或假设3成立,接着进行下一步实验。
步骤2:另取适量固体产物于试管中,向其中加入适量稀硫酸溶液,充分振荡若溶液变蓝色,结合步骤1,则假设3成立;

若溶液未变蓝色,结合步骤1,则假设1成立。

 

题目分析:Ⅰ、(1)无水硫酸铜遇水变蓝,可用量检验H2O的存在;CO2通入石灰水变浑浊,可用石灰水检验CO2

(2)根据资料卡片:CO能与PdCl2溶液反应生成黑色的钯粉,可知PdCl2把CO氧化为CO2,配平可得方程式:PdCl2  +  CO  +  H2O  =  Pd↓ +  CO2  +  2HCl

(3)不能互换D、E两装置位置,如果颠倒顺序后,E装置产生CO2,会对D对CO2的检验产生干扰。

(4)2次用到A装置,第一次:加热晶体前,通氮气可除去装置中的空气;第二次:加热晶体后,通氮气可把分解产生的气体产物全部赶出来。

Ⅱ、①假设3为假设1和假设2的综合:红色固体为Cu2O和Cu的混合物。

③根据题目所给资料卡片:Cu2O能溶于浓氨水形成络合物,设计步骤1:取适量固体产物于试管中,加入足量浓氨水,充分振荡使其溶解。若固体产物全部溶解,说明只含Cu2O,则假设2成立;若固体产物未全部溶解,则假设1或假设3成立,接着进行下一步实验。根据Cu2O与H2SO4发生歧化反应,生成CuSO4和Cu,设计步骤2:另取适量固体产物于试管中,向其中加入适量稀硫酸溶液,充分振荡;则若溶液变蓝色,结合步骤1,则假设3成立;若溶液未变蓝色,结合步骤1,则假设1成立。

单项选择题 A1/A2型题
阅读理解

The Internet has opened up a whole new on-line world for us to meet, chat (聊天) and go where we’ve never been before.

But just as in face-to-face communication, there are some basic rules of behavior that should be followed when online. The basic rule is simple: treat others in the same way that you would want to be treated. Imagine how you’d feel if you were in the other person’s shoes.

For anything you’re going to send, ask yourself: “Would I say this in front of the person?” If the answer is no, rewrite and reread. Repeat the process till you feel sure that you’d feel comfortable saying the words to the person’s face.

If someone in the chat room is impolite to you, your feeling is to fight back in the same manner. But try not to do so. You should either ignore (忽略) the person, or use your chat software (软件) to stop their messages. If it was caused by a disagreement with another member, try to fix the situation by politely discussing it. Remember to respect the beliefs and opinions of others in the chat room.

Everyone was new to the network once. Offer advice when asked by newcomers, as they may not be sure what to do or how to communicate. When someone makes a mistake whether it’s a stupid question or an unnecessarily long answer, be kind about it. If it’s a small mistake, you may not need to say anything. Even if you feel strongly about it, think twice before saying anything. Having good manners yourself doesn’t give you the right to correct everyone else.

If you do decide to tell someone about a mistake, point it out politely. At the same time, if you find you are wrong, be sure to correct yourself and apologize to those who you have offended (冒犯).

It is not polite to ask others personal questions such as their age, sex, and families. Unless you know the person very well, and you are both comfortable with sharing personal information, don’t ask such questions.

小题1:. When you send short messages to a person, you must       .

A.make sure that they don’t do harm to others

B.read them again and again

C.say something good to hear

D.repeat them later to the person’s face小题2:If you are hurt in the chat room by others, you should       .

A.fight back in the same way

B.take them seriously

C.pay no attention to them

D.be angry at them小题3:If a newcomer who communicates on line makes any mistakes, you       .

A.should point them out sharply

B.shouldn’t give any advice unless required by them

C.should say something about them

D.should correct them at once小题4:This passage mainly tells us       .

A.some rules of Internet communication

B.ways of sending messages

C.rules of the face – to – face communication

D.ways of making friends on the Internet