问题 选择题

下列说法中,正确的是(  )

①食盐灼烧时火焰呈黄色与久置的浓硝酸呈黄色原理不相同

②固体氢氧化钠存放在带塑料塞的广口瓶中

③熔点:钾>钠>钠钾合金

④向紫色石蕊试液中加入过量的Na2O2粉末,振荡后溶液呈蓝色

⑤向含有Na、SO42、HCO3、CO32的溶液中加入过量的Na2O2固体,Na和CO32的物质的量不变

⑥1 mol Na2O2与足量的水反应,转移的电子数为2 mol

⑦取用金属钠时,应将剩下的大块钠放回原瓶,实验结束,余下的钠屑应用乙醇处理(  )

A.①②⑦

B.①②③⑥

C.①②⑥⑦

D.①②④⑤

答案

答案:A

③钠钾合金<钾<钠;④先变蓝后褪色;⑤Na、CO32物质的量均增加;⑥1 mol Na2O2与足量水反应,转移的电子数为1 mol。

阅读理解

阅读下列短文,根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

In many parts of the world, cars play an important role in daily life and many societies would not exist without them.   1 But this is the prediction made by a team of transport researchers who are taken seriously, not only by government but also by car manufacturers(制造商).

The Human Science and Advanced Technology Institute at Loughborough in the UK is part of an international research program.   2 That will mean much saving, no accidents and better use of roads. The super-intelligent car of the 21st century will drive itself,   3 . Instead,we will have a choice of cars and change them as frequently as we change our clothing.

According to Dr.David Davis,who leads the research team,these predictions are based on the rising cost of the car culture,which had blocked up our cities,polluted our air, and caused more deaths than both world wars put together.

Davis says,cars will be fitted with some intelligent devices(装置) to regulate(调节) the distance between one car and another.   4 Computers are much safer drivers than people,so cars in a road train will be able to drive much closer together than cars driven by people.

By 2010,Dr.David Davis believes,car technology will give motorists a clear view of the road,whatever the weather conditions,by projecting an image(影像)of the road ahead on to the car’s windscreen.  5 Cars will be connected by an electronic bar to the car in front to form “road-trains”. “The front vehicle in such a train burns the normal amount of fuel.” says Davis. “ But all the others in the train would burn about ten percent of the normal amount,and so produce about ten percent of the pollution.”

A.The team there believes that by 2030 all cars will be computerized.

B.They believe that cars will become more important in 20 years.

C.And it will not be owned by one individual.

D.And by 2030, cars will travel in line, linked to each other electronically.E.So the idea that in 20 years’ time, no one will own cars may be hard to believe.

F.Every driver will use less fuel in the car he owns.

G.The car will automatically speed up, or slow down, to match the speed of the car in front.

实验题