问题 填空题

(15分)“低碳循环”已引起各国家的高度重视,而如何降低大气中CO2的含量和有效地开发利用CO2正成为化学家研究的主要课题。

(l)用电弧法合成的储氢纳米碳管常伴有大量的碳纳米颗粒(杂质),这种颗粒可用如下氧化法提纯,请完成该反应的化学方程式:

(2)将不同量的CO(g)和H2O(g)分别通入到体积为2L的恒容密闭容器中,进行反应,得到如下两组数据:

①实验2条件下平衡常数K= __________。

②实验3,若900℃时,在此容器中加入CO、H2O、CO2、H2均为1mol,则此时

____________(填“<”,“>”,“=”)。

③由两组实验结果,可判断该反应的正反应△H_____________0(填“<”,‘‘>”,“=”)。

(3)己知在常温常压下:

写出甲醇不完全燃烧生成一氧化碳和液态水的热化学方程式:________________________

①已知该反应的△H>0,简述该设想能否实现的依据:________。

②目前,在汽车尾气系统中装置催化转化器可减少CO和NO的污染,其化学反应方程式为__________。

(5)CO2在自然界循环时可与CaCO3反应,CaCO3是一种难溶物质,其Ksp=2.8× 10。CaCl2溶液与Na2CO3溶液混合可形成CaCO3沉淀,现将等体积的CaCl2溶液与Na2CO3溶液混合,若Na2CO3溶液的浓度为1×10mol/L,则生成沉淀所需CaCl2溶液的最小浓度为__________mol/L。

答案

(1)5、4、6、5、4、2、6;(2)①0.17;②<;③<;

(3)CH3OH(l)+O2(g)=CO(g)+2H2O(l)  ∆H= -442.8KJ/mol;

(4)①该反应是焓增、熵减的反应,任何温度下均不能自发进行;②2CO+2NO2CO2+N2

(5)1.12×10-4

题目分析:(l)该反应是氧化还原反应。根据氧化还原反应中电子转移数目与化合价升降总数相等可得该反应的方程式,配平为5C+4KMnO4+6H2SO4=5CO2↑+4MnSO4+2K2SO4+6H2O;(2) ①实验2条件下平衡常数=0.17。②实验3,若900℃时,在此容器中加入CO、H2O、CO2、H2均为1mol,由于生成物的浓度增大的多于反应物增大的浓度,因此在此时<。③在实验1条件下平衡常数可见升高温度,化学平衡常数减小。说明升高温度,平衡逆向移动。根据平衡移动原理。升高温度,化学平衡向吸热反应方向移动。逆反应方向为吸热反应,实验正反应为放热反应。因此该反应的正反应△H<0。(3) (①-②)÷2+③×2,整理可得CH3OH(l)+O2(g)=CO(g)+2H2O(l)  ∆H= -442.8KJ/mol;①由已知条件可知:该反应是焓增、熵减的反应,所以在任何温度下均不能自发进行;②目前,在汽车尾气系统中装置催化转化器可减少CO和NO的污染,使其转化为无毒的大气的成分。该反应的化学反应方程式为2CO+2NO2CO2+N2;(5) Ksp=c(Ca2+)·c(CO32-)=2.8×10.由于溶液等体积混合后离子的浓度都减小一半,混合后c(CO32-)=5×10-5mol/L,所以Ca2+离子浓度的最小值是1/2c(Ca2+)×1/2×1×10≥2.8×10.解得c(Ca2+)≥1.12×10-4mol/L。

阅读理解

阅读下面的短文,为文中空白处选择恰当的句子。

     The 1990s saw great changes in the way people communicate. People could send mail without going to

the post office, and go shopping without leaving home. 1_____ The cause of this great change was the

Internet.

     The idea for the Internet began in the early 1960s in the United States. The Department of Defense

wanted to connect their computers together in order to share private information. In 1969, the ARPA (an

early from of the Internet) first connected computers at four American universities. 2_____ In 1972, scientists

shared ARPA net with the world. They created a way to send person-to-person messages using ARPA net.

This was the beginning of e-mail. 

     3_____ However, most people were not using the Internet. Then, in the 1980s, personal computers became more common. In the early 1990s, two important things happened: the birth of the World Wide Web in 1991,

and the creation of the first Web browser (浏览器) in 1993. The Web made it easier to find information on the

Internet, and to move from place to place using links. The Web and browser made it possible to see information at a website with pictures, sound, and words.

     Today, millions of people connect to the Internet to send e-mails, visit website, or store information on

servers. 4_____ And computers are changing how we learn, work, shop, and communicate.

A. Computers are now an important part of our lives.

B. One computer successfully sent information to another.

C. Words like e-mail and download became part of people's vocabulary.

D. Over the next few years, there was a lot of progress made in the world of computing.

单项选择题