2N2O5(g)═4NO2(g)+O2(g)△H=+56.8kJ/mol自发进行

题型:选择题

问题:

2N2O5(g)═4NO2(g)+O2(g)△H=+56.8kJ/mol自发进行的原因是(  )

A.是吸热反应

B.是放热反应

C.是熵减少的反应

D.熵增大效应大于能量效应

考点:焓变、反应热
题型:选择题

正常情况下储粮水分的变化是怎样的?

题型:选择题

While students in Hainan are quite used to clear skies, Beijing teenagers are not so lucky. As another warm winter approaches, the city can expect the normal clouds of smoke caused by air pollution.

But things could start to get better soon. The government is co-operating with a US-based environmental protection agency to update existing buses and trucks with clean fuel technology. The new technology could reduce air pollutants in existing diesel vehicles (柴油机) by 40 per cent. The programme will begin by testing buses in Beijing to see if the technology can be applied to them.

“We encourage the development of public transportation. But at the same time we need to reduce pollution from them,” said an official.

Efforts are being made to improve the capital’s environment with tighter controls on emissions (排放). Some heavily polluting factories and construction sites, such as those owned by the steel giant Shougang Group, have been asked to cut production in November and December or be closed.

Beijing was the third polluted city in the world at the end of last century, according to the UN. But thanks to recent measures, the capital has made some progress. Last year 224 clear days were rated as having good air quality. In 1998 the air quality index (指数) gave just 100 days as good.

“I am glad to see an improvement,” said a Senior 1 boy living in the northwest of Beijing. “Compared to other places, the air quality of Beijing is still worrying though. I hate the pollution. Once I was riding my bike in the morning when I almost had a traffic accident because I couldn’t see a car only metres away from me in frog.”

In early October, the skies were covered by such a thick fog that a display show by the visiting French air force was called off.

Rapid development, industry, traffic fumes (烟) and sandstorms from the desert all contribute to the city’s bad air.

小题1:The passage is mainly about ________?

A.a programme to improve Beijing’s air quality

B.progress made in Beijing’s air quality

C.Beijing’s air pollution

D.the difference between Hainan and Beijing小题2:Which of the following is not the measure taken or to be taken to improve Beijing’s air?

A.Clean fuel technology will be used in public transportation.

B.Some factories have been asked to cut production.

C.Some construction sites have been told to be closed.

D.A display show of airplanes has been called off.小题3:We can infer from the passage that, with the aim of being an ecological (生态的) city by the 2008 Olympics, ________.

A.far more still needs to be done

B.nothing else needs to be done

C.all traffic has to be closed

D.the development of the city has to be slowed down小题4:Which is not correct according to the passage?

A.Beijing’s air quality is getting worse and worse.

B.Development, industry, traffic fumes and sandstorms are all the causes of bad air quality.

C.Clouds of smoke in the sky is the common feature in the winter of Beijing.

D.The government is making every effort to stop air pollution.

题型:选择题

车站值班员发现车站与调度所间CTC通信故障时,应及时报告列车调度员,并通知电务人员抢修,由车站在()模式下组织车站作业。

A、车站控制

B、CTC控制

C、分散自律

D、列调控制

题型:选择题

化学和容积控制系统﹝压水堆﹞ chemical and volume control system

题型:选择题

有劳动能力的劳动适龄人口包括()。

A.家务劳动者

B.劳动年龄以外实际就业人口

C.16岁以上的劳动人口

D.失业人口

E.全体人口

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