问题 选择题

设nA为阿伏加德罗常数的数值,下列说法正确的是(  )

A.常温下,4g CH4含nA个C-H共价键

B.1 mol Fe与足量稀HNO3反应,转移个2nA个电子

C.1L 0.1 mol/L NaHCO3溶液中含有0.1nA个HCO3-

D.常温常压下,22.4L的NO2和CO2混合气体含有2nA个O原子

答案

A、4g CH4物质的量为0.25mol,分子中含C-H共价键4×0.25×nA=nA个,故A正确;

B、稀硝酸过量,生成硝酸铁,转移电子应该是3 nA个电子,故B错误;

C、碳酸氢根离子水解,应该是小于0.1nA个HCO3-;故C错误;

D、条件错误,应为标准状况,故D错误;

故选A.

解答题
阅读理解

E

Almost every day we come across situations in which we have to make decisions one way or another. Choice, we are given to believe, is a right. But for a good many people in the world. In rich and poor countries, choice is a luxury, something wonderful but hard to get, not a right. And for those who think they are exercising their right to make choices, the whole system is merely an illusion, a false idea created by companies and advertiser, hoping to sell their products.

The endless choice gives birth to anxiety in people’s lives. Buying something as basic as a coffee pot is not exactly simple. Easy access to a wide range of everyday goods leads to a sense of powerlessness in many people, ending in the shopper giving up and walking away, or just buying an unsuitable item(商品) that is not really wanted. Recent studies in England have shown that many electrical goods bought in almost every family are not really needed. More difficult decision-making is then either avoided or trusted into the hands of the professionals, lifestyle instructors, or advisors.

It is not just the availability of the goods that is the problem, but the speed with which new types of products come on the market. Advances in design and production help quicken the process Products also need to have a short lifespan so that the public can be persuaded to replace them within a short time. The typical example is computers, which are almost out-of-date once they are bought. This indeed makes selection a problem. Gone are the days when one could just walk with case into a shop and buy one thing; no choice, no anxiety.

小题1: What does the author try to argue in Paragraph 1?

A.The exercise of rights is a luxury.

B.The practice of choice is difficult.

C.The right of choice is given but at a price.

D.Choice and right exist at the same time.小题2: Why do more choices of goods give rise to anxiety?

A.Professionals find it hard to decide on a suitable product.

B.People are likely to find themselves overcome by business persuasion.

C.Shoppers may find themselves lost in the broad range of items.

D.Companies and advertisers are often misleading about the rage of choice.小题3:By using computers as an example, the author wants to prove that    .

A.advanced products meet the needs of people

B.products of the latest design fold the market

C.competitions are fierce in high-tech industry

D.everyday goods need to be replaced often小题4: What is this passage mainly about?

A.The variety of choices in modern society.

B.The opinions on people’s right in different countries

C.The Problems about the availability of everyday goods.

D.The helplessness in purchasing decisions