问题 实验题

标准状况下,将1L可能含有N2,H2,CO,NH3,NO2,H2S杂质的无色SO2气体,依次通过如下图所示的装置。(各容器中液体均为足量)

其变化情况是:①气体通过A瓶,浓H2SO4无明显变化,气体体积无变化;②气体通过B瓶,饱和Na2CO3溶液质量增加0.5g,气体体积无变化;③气体通过C瓶后,再通过D管,灼热的CuO中有红色物质生成。冷却后,气体体积变为888ml(标准状况);④将上述气体通过E后,再通入F中,澄清石灰水变浑浊,同时增重1.54g;⑤气体经过干燥管P后,在量筒H中,收集到水104ml。根据以上实验回答:

(1)混合气体中SO2的体积分数为______________。

(2)混合气体中含有的杂质为______________。

(3)混合气体中是否含有H2、CO杂质;若有,指出其体积;若无,说明理由。

a.H2:____________________________________________________________________;

b.CO: ____________________________________________________________________。

答案

(1)56%;(2)N2,H2,CO;(3)H2∶112mL;(4)CO∶224mL

①气体通过浓H2SO4,体积无变化,说明无NH3和H2S(H2S与浓H2SO4发生氧化还原反应)。

②气体通过饱和Na2CO3溶液质量增加0.5g,发生了反应:

SO2+Na2CO3=Na2SO3+CO2   Δm

22.4L    ∶   44g   (64-44)g

V(SO2)    ∶   m(CO2)  0.5g

V(SO2)=0.56L    m(CO2)=1.1g

φ(SO2)=0.56L/1L×100%=56%

③通过灼热的CuO有红色物质生成,说明有还原性气体H2或CO或两者皆有。

④通入澄清石灰水变浑浊,说明有CO2(由两部分组成),且为1.54g,则③中的还原性气体必含CO:

CO ~    CO2 ~  Ca(OH)2

22.4L     4g

V(CO)    (1.54g-1.1g)

V(CO)=22.4L×0.44g/44g=0.224L=224mL

⑤最后得到的气体只能是N2,且V(N2)=V(H2O)=104mL,S则V(H2)=1000ml-888mL=112mL。

判断题
阅读理解

阅读理解。

     A new generation addiction is quickly spreading all over the world. Weboholism, a twentieth century

disease, affects people from different ages. They surf the Net, use email and speak in chat rooms. They

spend many hours on the computer, and it becomes a compulsive habit. They cannot stop, and it affects

their lives. Decades ago, no one thought that using computers could become compulsive behavior that

could affect the social and physical life of computer users. This obsessional behavior has affected

teenagers and college students. They are likely to log on computers and spend long hours at different

websites.

     They become hooked on computers and gradually their social and school life is affected by this

situation. They spend all free time surfing and don't concentrated on homework, so this addiction

influences their grades and success at school. Because they can find everything on the websites, they

hang out there. Moreover, this addiction to websites influences their social life.

     They spend more time in front of computers than with their friends. The relation with their friends

changes. The virtual life becomes more important than their real life. They have a new language that

they speak in the chat rooms and it causes cultural changes in society.

     Because of the change in their behavior, they begin to isolate themselves from the society and live

with their virtual friends. They share their emotions and feelings with friends who they have never met

in their life. Although they feel confident on the computer, they are not confident with real live friends

they have known all their life. It is a problem for the future. This addictive behavior is beginning to affect

the entire world.

1. The main idea of the passage is about ______.  

A. the cause of weboholism  

B. the advantage of weboholism

C. the popularity of weboholism  

D. the influence of weboholism

2. The underlined world "obsessional" in the second paragraph probably means ______.

A. attractive  

B. addictive  

C. professional  

D. potential  

3. We can infer from the passage that ______.

A. weboholism has the greatest effect on teenagers

B. students can hardly balance real and virtual life

C. people are addicted to games on the Internet          

D. virtual life is more vivid and attractive anyway

4. Which of the following is NOT true of weboholism?

A. It contributes to the development of the web.

B. The chat room language may change social culture.

C. The problem will be getting more and more serious later.      

D. People addicted to the web often become inactive in real life.

5. The author's attitude towards weboholism is that of being ______.

A. optimistic    

B. neutral      

C. critical  

D. acceptable