试题与答案

某校化学兴趣小组用浓盐酸与二氧化锰加热反应来制取并收集氯气,装置如下: (1)写

题型:填空题

题目:

某校化学兴趣小组用浓盐酸与二氧化锰加热反应来制取并收集氯气,装置如下:

(1)写出该反应的化学方程式______;反应中,氧化剂和还原剂的物质的量之比为______

(2)兴趣小组的某些同学准备在烧杯中加入下列溶液中的一种来吸收残余氯气,你认为其中错误的是(填序号)______ 

A.氢氧化钠溶液   B.碳酸钠浓溶液

C.浓硫酸         D.饱和氯化纳溶液.

答案:

(1)浓盐酸有还原性,二氧化锰有氧化性,浓盐酸和二氧化锰能发生氧化还原反应生成氯化锰、氯气和水,其反应为MnO2+4HCl(浓)

  △  
.
 
MnCl2+Cl2↑+2H2O;

该反应中化合价的变化为:MnO2→MnCl2 ,锰元素由+4价→+2价,1mol二氧化锰得2mol电子;

HCl→Cl↑,氯元素由-1价→0价,1molHCl失去1mol电子,所以其最小公倍数为2,二氧化锰的计量数为1,作还原剂的HCl的计量数为2,物质的量之比等于计量数之比,所以氧化剂和还原剂的物质的量之比为 1:2.

故答案为:MnO2+4HCl(浓)

  △  
.
 
MnCl2+Cl2↑+2H2O;1:2;

(2)氯气和水反应生成盐酸和次氯酸,盐酸和次氯酸具有酸性,盐酸是强酸,能和碱或弱酸盐反应,而氯气不与浓硫酸、氯化钠反应,则不能用来吸收残余氯气.

故答案为:CD.

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题型:阅读理解

It should be very clear that we live in a most spectacular(壮观的)time. It’s a time when information is of primary importance. It’s a time when new information technologies are fundamentally transforming the world in every aspect. Among the changes, which have come upon modern society, the ones in education are probably the most obvious and influential. New information technologies are accelerating changes in education, at the same time presenting revolutionary tools with the potential to make education more efficient and more effective than ever.

The application of new information technologies has remarkably promoted the process of education. Online learning is probably the best case in point. As is often the case with “technology”, online learning may appear to be horrible; it can sound like alphabet soup sometimes. Now let’s see whether you can understand all this. You can participate in CBT at a CLC via the convenience of IDL. What does it all mean? Let me translate: GBT—Computer-Based Training; CLC—Computer Learning Center; IDL—Interactive Distance Learning. Sound complicated? Not really. Online learning is much less complicated than it seems. Students can learn at any time, anywhere, at any speed. They can make their own learning schedules and follow their own paths to suit their lifestyles. In my university, every semester there’re several online courses available, which need no class meetings or paper materials. The only thing I have to do is just to get online regularly as I wish, and download necessary learning materials. Then everything I need to know about the course is only a click away.

But online learning is not perfect; it’s like the microwave oven: it does some things better, but it is not a complete replacement for the traditional model. The traditional classroom model for education and learning is hard to leave behind. Because humans are social creatures, there’re times when we need to see each other face-to-face for interactive learning. A social and personal connection often builds effective teams, solves problems, and inspires confidence. So one possible solution is to combine online learning with the old traditional classroom learning , which not only makes the learning process faster and cheaper, but also highlights the interactions between teachers and students.

The bottom line: the Internet is the most important educational tool in the information age and online learning will become a main part of every individual’s learning experience in the future. That’s exactly how we will move knowledge from the ones who have it to the ones who need it faster and cheaper, and that’s how we’re going to survive in the information age.

小题1:The most suitable title for the passage should be “___________.”

A.Education in the information age

B.Advantages and disadvantages of online learning

C.Online learning vs classroom learning

D.How to survive in the information age小题2:In Paragraph 3 the microwave oven is mentioned as an example to indicate that_________.

A.online learning needs improving

B.online learning doesn’t suit everyone

C.online learning will exist alongside the traditional model

D.online learning is more advanced than the traditional model小题3:Which of the following descriptions about online learning is NOT true according to the passage?

A.It is more efficient and effective.

B.It is convenient to both teachers and students.

C.It stresses interactions between teachers and students.

D.It is a cheaper way of learning.小题4:It can be inferred from the passage that________.

A.not all the people are in favor of online learning

B.it is not easy to combine online learning with classroom learning

C.in the future all the courses will be available online

D.in a sense our survival in the world depends on online learning

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