问题 判断题

工艺气气流速度过慢,会造成甲醇洗涤塔液泛。

答案

参考答案:错

解析:工艺气气流速度过快,会造成甲醇洗涤塔液泛。

问答题

化学与社会发展

据2013年5月21日央视焦点访谈报道,继成都、南京、大连、福州、厦门之后,昆明再次爆发抵制PX化工项目的游行活动,PX甚至被人们贴上“剧毒物质”、“致癌物质”的标签,导致国人闻之色变.PX是“对二甲苯”(para﹣xylene)的英文缩写,化学式是C8H10.PX究竟是一种什么样的物质?是否像舆论所说的如此可怕?请阅读下列信息:

PX的性质①无色透明液体;②熔点13.2℃、沸点138.5℃;③密度0.86g/cm3;④有芳香气味;⑤可燃;⑥有挥发性,但比汽油低;⑦低毒,毒性与汽油相当;在致癌性上,按国际惯例属于第三类致癌物,即缺乏证据证明其具有致癌性;⑧遇火可爆炸,但爆炸性比汽油低(爆炸极限为1.1%~7.0%).
PX的用途化学工业的重要原料,用于纺织、塑料、建材、医药、农药等方面,如雪纺衣物、尼龙绳、塑料保险盒和保鲜袋等,涉及到衣食住行的方方面面.目前,我国每年需要PX1500万吨,而产量仅为800万吨,还需要进口700万吨;PX的价格与供应掌握在外国人手里.有趣的是,在游戏活动中,很多市民戴的口罩、穿的服装都是用PX做的.
 

根据上述信息,请你回答下列问题:

(1)根据物质的组成对PX分类.它属于        

(2)上表中属于PX物理性质的是(填性质代号)            

(3)根据PX的性质,从防止环境污染和安全的角度,应如何保存和储运PX?        

(4)试写出PX在空气中完全燃烧反应的化学方程式.                           

(5)对于PX项目的利与弊,请从PX的性质、变化和用途的角度谈谈你的看法                                                                                                                                                 

阅读理解

阅读理解。

    While I was in 9th grade, I built a circuit for the traffic system of our city. After getting the first prize, I

got this valuable advice from my father, "Do whatever interests you, and don't let the work challenge you,

make sure you are challenging that work."

    I have always preferred the projects which are challenging and related to real life problems. I clearly

remember building a shipping program several years ago. I divided the whole project into several small

sections. When I understood it clearly, used my brainstorming skill on it, and gave some basic ideas. Then

I asked my professor for help before jumping into coding. At first, I did not know how to ask questions

correctly and always asked the question "How do I do it?" As I kept working and discussed with my professor,

I became more comfortable and those"How" questions soon turned into "What if I do this and that" types o

f questions.

    It took me four days to write the code. The desire to solve the problem kept me sleepless all nights

brainstorming in even greater details. Every time I saw my program running smoothly, I exploded with joy.

I still remember the last day of my work. I was getting some problem and didn't know what to do. At that

moment, a man came in to clean. He has headphones, and he was dancing while cleaning the room. Seeing

this, I burst out laughing. That moment calmed me. I regained energy and interest and started to work again,

and soon I fixed the problem.

    My success in the project proved that breaking up a large problem into small parts could help find a

possible solution. Discussing the problem with others was also very beneficial. Now I have gained the

confidence to attempt any kind of project.

1. According to the passage, the writer was interested in _____. [ ]

A. developing traffic systems

B. doing challenging projects

C. winning great prizes

D. writing different codes

2. The writer asked the question "How do I do it" at first because _____.[ ]

A. he had no clear idea about his program

B. he was too shy to express himself

C. he wanted to he understood easily

D. he preferred this kind of question

3. We learn from the passage that the writer's shipping program _____.[ ]

A. would benefit people a lot

B. was done together with others

C. was difficult and needed patience

D. cost much money and energy

4. What would be the best title of the passage? [ ]

A. Do It Yourself

B. No Pains, No Gains

C. Learning with interest

D. Practice Makes Perfect