问题 填空题

(1)在100 ℃恒温条件下将0.100 mol的N2O4充入体积为1 L的真空密闭容器中,发生反应:N2O4(g)2NO2(g) ΔH>0。隔一定时间对该容器内的物质进行分析,得到如下数据:

t/s

c/(mol·L-1)  

020406080100
c(N2O4)/(mol·L1)0.100a0.5b0.4b  
c(NO2)/(mol·L-1)00.060bc1c2c3
 

请回答下列问题:

①表中a=________,在0~20 s内N2O4的平均反应速率为_______mol·(L·s)-1

②已知100 ℃时该反应的平衡常数为0.36,则表中b、c1、c2的大小关系为________,c3=________mol·L-1,达到平衡时N2O4的转化率为________________________________。

(2)室温下,把SiO2细粉放入蒸馏水中,不断搅拌,能形成H4SiO4溶液,反应原理如下:

SiO2(s)+2H2O(l)H4SiO4(aq) ΔH

①写出该反应的化学平衡常数K的表达式:____________________________。

②实际上,在地球的深处,由于压强很大,固体、液体都会受到影响。在一定温度下,在10 000 m以下的地球深处,上述反应的方向是________(填“正方向”、“逆方向”或“不移动”),理由是_______________________________。

答案

(1)①0.070 1.5×10-3 ②b<c1=c2(或c1=c2>b) 0.120 60% (2)①K=c(H4SiO4) ②正方向 由于固体、液体都会受到大气压强的影响,故此时K的表达式应为K=,增大压强时,平衡向正反应方向移动

(1)根据表中数据和反应方程式可得(0.100-a)∶0.060=1∶2,解得a=0.070;由(0.100-0.5b)∶b=1∶2,解得b=0.100;由(0.100-0.4b)∶c1=1∶2,解得c1=0.120,此时=0.36,即第60 s时反应已达平衡状态。

(2)①由于情境陌生,在书写化学平衡常数K的表达式时容易把水和二氧化硅写上。仔细审题会发现二氧化硅是固体,由于H4SiO4溶液的浓度很小,水的浓度可看成常数,故K=c(H4SiO4)。

②压强增大,分析平衡移动的方向,注意在压强很大的条件下,此时压强对固体、液体的影响不能忽略不计。

填空题
单项选择题

One reason many politicians behave badly these days is that we spend less time thinking about what it means to behave well. This was less of a problem in past centuries when leaders, teachers and clergy held detailed debates over what it meant to have good character.

In the 18th century, for example, Edmund Burke composed a long, famous passage defining the standards of political excellence. In the 19th century, Anthony Trollope wrote a series of popular novels fussing over what it means to behave well in political life. Trollope’s view was different than ours. Many Americans today assume that people are born with a good Inner Self but get corrupted by politics. American voters are always looking for the Innocent Outsider who can come in and bring sweeping change.

Trollope admired Prudent Insiders, not Innocent Outsiders. His most admirable characters have been educated by long experience. They have grown mature by exercising responsibility. They have been ennobled by custom and civilization. In his books, powerless outsiders often behave self-indulgently and irresponsibly. Those who are in government have to grapple with the world as it really is.

Trollope’s ideal politicians—who have names like Plantagenet Palliser, Joshua Monk and the Duke of St. Bungay put service before independence. Their party and their country have asked them to accept certain duties and face certain problems, and they just get on with it. They are more weighty, but also more boring.

Trollope’s ideal politicians share certain traits. They are reserved, prudent and scrupulous. They immerse themselves in dull practical questions like, say, converting the currency system. They are not sweeping thinkers, but they make sensitive discriminations about the people and the circumstances around them. They learn to operate within the constraints imposed by their idiom, and they don’t whine or complain about those constraints. They develop delicate understandings of what is required in a given place in time.

Trollope’s ideal leaders are not glamorous celebrities of the sort we have come to long for since J. F. Kennedy. They are more like seamen or carpenters. They are judged by their professional craftsmanship. They are thin-skinned about any moral transgression they might commit and rigorously honest when judging themselves. They try to make things better but are acutely aware that everything they do might make things worse. Trollope’s leaders don’t embrace change quickly but have to be dragged into embracing it after much interrogation, and the change they prefer is incremental.

Trollope praises one of his prime ministers, Plantagenet Palliser, for "that exquisite combination of conservatism and progress which is his country’s present strength and her best security for the future. " Trollope’s readers would have come away from his books with a certain model for how practical people should behave, which they could either copy or argue with. I’m not sure his exemplars could thrive amid the TV politics of today, which calls for grand promises and bold colors. But there are prudent, reserved people in government even now.

A Prudent Insider is one()

A. who can come up with ideas in reforming the outside world

B. who shows little concern about the outside world as it really is

C.whose well-trained mind enables him to make sound judgment

D. whose education helps him to free himself from customs and traditions