问题 实验题

(10分)下图甲是课本中验证铜和浓硝酸反应的装置,乙、丙是师生对演示实验改进后的装置:

(1)      写出铜和浓硝酸反应的离子方程式                                 。

(2)和甲装置相比,乙装置的优点有                                         

(3)为了进一步验证NO2和水的反应,某学生设计了丙装置,做实验时先关闭弹簧夹

        ,再打开弹簧夹            ,才能使NO2气体充满②试管。 

(4)当气体充满②试管后,将铜丝提起与溶液脱离,欲使烧杯中的水进入②试管应如何操

                                                                           

(5)②试管中的NO2和水充分反应后,所得溶液物质的量浓度的最大值是

             (气体体积按标准状况计算)。

答案

(1)Cu + 4H+ + 2NO3_ = Cu2+ + 2NO2↑+ 2H2O   (2分)

(2)①可以控制反应。(1分)②吸收NO2气体,防止污染环境。(1分)

(3)关闭c;打开a、b。(2分)

(4)先关闭b,再关闭a, 然后打开c,用手捂住(热水、热毛巾、加热)试管②。(合理答案均给分) (2分)

(5)1/22.4mol·L-1或0.045mol·L-1  (2分)

单项选择题

For good or ill, globalization has become the economic buzz-word of the 1990s. National economies are undoubtedly becoming steadily more integrated as cross-border flows of trade, investment and financial capital increase. Consumers are buying more foreign goods, a growing number of firms now operate across national borders, and savers are investing more than ever before in far-flung places.

Whether all of this is for good or ill is a topic of heated debate. One positive view is that globalization is an unmixed blessing, with the potential to boost productivity and living standards everywhere. This is because a globally integrated economy can lead to a better division of labor between countries, allowing low-wage countries to specialize in labor-intensive tasks while highwage countries use workers in more productive ways. It will allow firms to exploit bigger economies of scale. And with globalization, capital can be shifted to whatever country offers the most productive investment opportunities, not trapped at home financing projects with poor returns.

Critics of globalization take a gloomier view. They predict that increased competition from low-wage developing countries will destroy jobs and push down wages in today’s rich economies. There will be a race to the bottom as countries reduce wages, taxes, welfare benefits and environmental controls to make themselves more competitive. Pressure to compete will erode the ability of governments to set their own economic policies. The critic also worry about the increased power of financial markets to cause economic havoc, as in the European currency crises of 1992 and 1993, Mexico in 1994~1995 and South-East Asia in 1997.

As a result of globalization, all of the following might happen EXCEPT ().

A. unemployment rate in rich economies might increase

B. competitiveness of low-wage countries might weaken

C. environmental problems in some countries might worsen

D. economic havoc might occur in some parts of the world

单项选择题