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问题 问答题

储氢纳米碳管研究成功体现了科技的进步．但用电弧法合成的碳纳米管常伴有大量的杂质--碳纳米颗粒．这种碳纳米颗粒可用氧化气化法提纯．其反应式为：3C+3K2Cr2O7+8H2SO4=3CO2+2K2SO4+2Cr2（SO4）3+8H2O

①此反应的氧化剂是______，氧化产物是______；

②H2SO4在上述反应中表现出来的性质是______（填选项序号）

A．酸性　　　　　　　B．氧化性　　　　　C．吸水性　　　　D．脱水性

③由此可知上述反应所用硫酸应为______（填“浓”或“稀”）硫酸．

④请写出碳单质与硫酸反应时的化学方程式：______．

答案

①因反应中Cr元素的化合价降低，则K2Cr2O7为氧化剂，C元素化合价升高，C为还原剂，所以CO2为氧化产物，故答案为：K2Cr2O7；CO2；

②该反应中，硫酸中各元素的化合价不变，反应生成硫酸盐，体现硫酸的酸性，故答案为：A；　　

③因浓硫酸具有强氧化性，上述反应中硫酸作酸，则应为稀硫酸，故答案为：稀；　　

④碳与浓硫酸反应生成二氧化碳、二氧化硫和水，该反应为C+2H2SO4（浓）

△
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CO2↑+2SO2↑+2H2O，故答案为：C+2H2SO4（浓）
△
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CO2↑+2SO2↑+2H2O．

单项选择题

单侧肺通气时，哪项与预防低氧血症不符（）

A.保持有效通气

B.血氧饱和度维持90%

C.吸入50%氧

D.约30分钟膨肺一次

E.维持足够麻醉镇痛
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问答题

A couple of years ago a group of management scholars from Yale and the University of Pittsburgh tried to discover if there was a link between a company’s success and the personality of its boss. (46)To work out what that personality was, they asked senior managers to score their bosses for such traits as an ability to communicate an exciting vision of the future or to stand as a good model for others to follow. When the data were analyzed, the researchers found no evidence of a connection between how well a firm was doing and what its boss was like. As far as they could tell, a company could not be judged by its chief executive any better than a book could be judged by its cover.
(47)A few years before this, however, a team of psychologists from Tufts University, led by Nalini Ambady, discovered that when people watched two-second-long film-clips of professors lecturing, they were pretty good at determining how able a teacher each professor actually was.
Now, Dr Ambady and her colleague, Nicholas Rule, have taken things a step further. (48)They have shown that even a still photograph can convey a lot of information about competence—and that it can do so in a way which suggests the assessments of all those senior managers were nonsense.
Dr Ambady and Mr. Rule showed 100 undergraduates the faces of the chief executives of the top 25 and the bottom 25 companies in the Fortune 1,000 list. Half the students were asked how good they thought the person they were looking at would be at leading a company and half were asked to rate five personality traits on the basis of the photograph. (49) These traits were competence, dominance, likability, facial maturity (in other words, did the individual have an adult-looking face or a baby-face) and trustworthiness.
And Dr Ambady and Mr. Rule were surprised by just how accurate the students’ observations were. The results of their study, which are about to be published in Psychological Science, show that both the students’ assessments of the leadership potential of the bosses and their ratings for the traits of competence, dominance and facial maturity were significantly related to a company’s profits.
(50)Sadly, the characteristics of likability and trustworthiness appear to have no link to company profits, suggesting that when it comes to business success, being warm and fuzzy does not matter much (though these traits are not harmful).
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