问题 推断题

已知:A是相对分子质量最小的氧化物,D是最简单的有机物,也是天然气中最主要的成分。请分析A、B、C、D、E五种物质之间的变化关系,回答有关问题。

(1)B与D反应时发出    火焰,其化学方程式为                        

(2)请写出A→B+C的化学方程式:                                ;该反应的基本类型是                         

答案

(1)蓝色 CH4 + 2O2点燃 CO2 + 2H2O  (2)2H2O 通电 2H2↑+ O2 ↑ 分解

题目分析:解答这种类型的试题,就好比破案,寻找出对破案游泳的线索,找准突破口(又称“题眼”)是题的关键,突破口主要包括:沉淀、气体、溶液的特殊颜色;特征的反应、反应条件、反应形式、转化规律、基本类型等,根据突破口进行,对所给信息通过综合分析和思维加工,进行推理、比较、论证等,从而得出正确答案,(1)像这题的“题眼”就是A是相对分子质量最小的氧化物,再加上A →B+C的条件是通电, 可以推知A是水,则B、C就是氢气或氧气,D是最简单的有机物,也是天然气中最主要的成分.可以推知是甲烷,B+D充分燃烧生成水和E,所以不难推知B为氧气,C为氢气,那E自然是二氧化碳,甲烷燃烧发出蓝色火焰,化学方程式为:CH4 + 2O2点燃 CO2 + 2H2O

(2)A→B+C的化学方程式:2H2O 通电 2H2↑+ O2 ↑,属于“一变多”,是分解反应

单项选择题

With the spread of inter-active electronic media a man alone in his own home will never have been so well placed to fill the inexplicable mental space between cradle and crematorium. So I suspect that books will be pushed more and more into those moments of travel or difficult defecation (1) people still don’t quite know what to do with.

When people do read, I think they’ll want to feel they are reading literature, or (2) something serious. (3) you’re going to find fewer books presenting themselves as no-nonsense and (4) assuming literary pretensions and being packaged as works of art. We can expect an extraordinary variety of genre, but with an underlying (5) of sentiment and vision.

Translators can only (6) from this desire for the presumably sophisticated. We can look forward to lots of difficult names and fantastic stories of foreign parts enthusiastically (7) by the overall worship of the "global village’. Much of this will be awful and some wonderful, (8) don’t expect the press or the organizers of prizes to offer you much help in making the appropriate distinctions. They will be chiefly (9) in creating celebrity, the greatest enemy of discrimination, but a good prop for the (10) consumer.

Every ethnic grouping over the world will have to be seen to have a great writer—a phenomenon that will (11) a new kind of provincialism, more chronological than geographic, (12) only the strictly contemporary is talked about and (13) Universities, including Cambridge, will include (14) their literature syllabus novels, written only last year. (15) occasional exhumation for the Nobel, the achievements of ten or only five years ago will be largely forgotten.

In short, you can’t go too far wrong when predicting more of the same. But there is a (16) side to this—the inevitable reaction against it. The practical things I would like to see happen--publishers seeking less to (17) celebrity through extravagant advertising, (18) and magazines (19) space to reflective pieces—are rather more improbable than the Second Coming(耶稣复临). But dullness never quite darkens the whole planet. In their own idiosyncratic fashion a few writers will (20) be looking for new departures.

Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on ANSWER SHEET 1.6()

A.benefit

B.derive

C.differ

D.deviate

单项选择题