问题 问答题

800K时将1mol CO和1mol H2O(g)充入体积为1L的固定容积的反应器中,在某条件下达到化学平衡状态:CO(g)+H2O(g)⇌CO2 (g)+H2 (g),此时有

2
3
的CO转化为CO2

(1)该平衡混合物中CO2的体积分数为______

(2)写出该反应的化学平衡常数表达式______,并计算出平衡常数为______

(3)若使平衡向正方向移动,则下列说法中正确的是______(填序号)

①生成物的物质的量一定增加②生成物的体积分数一定增加:③反应物的转化率一定增大;④反应物的浓度一定降低;⑤正反应速率一定大于逆反应速率;⑥一定使用了催化剂.

(4)在相同条件下,若向容器中充入1mol CO2、1mol H2和1mol H2O,则达到平衡时与(1)中平衡相比较,平衡应向______(填“正反应方向”、“逆反应方向”或“不移动”),此时平衡混合物中CO2的体积分数为______(提示:3的平方根为1.732)

答案

利用三段式法求平衡时各组分个浓度,

             CO(g)+H2O(g)⇌H2(g)+CO2(g),

起始(mol):1             1                  0               0

转化(mol):

2
3
             
2
3
                 
2
3
              
2
3

平衡(mol):1-

2
3
=
1
3
         1-
2
3
=
1
3
           
2
3
              
2
3

 (1)反应前后气体的体积不变,所以平衡时,混合气体的总的物质的量为1mol+1mol=2mol,

所以平衡混合物中CO2的体积分数为

2
3
mol
2mol
=
1
3

故答案为:

1
3

(2)化学平衡常数=生成物平衡浓度系数次方之积与反应物平衡浓度系数次方之积的比,

故该反应的平衡常数表达式k=

c(H2)c(CO2)
c(CO)c(H2O)
,反应在同一容器内进行,体积相同,方程式中各物质的化学计量数都是1,所以在计算中均可用物质的量数值代替浓度数值,所以k=
c(H2)c(CO2)
c(CO)c(H2O)
=
2
3
×
2
3
1
3
×
1
3
=4.

故答案为:k=

c(H2)c(CO2)
c(CO)c(H2O)
;=4.

(3)平衡向向正方向移动,

①不论改变何条件,平衡向向正方向移动,生成物的物质的量一定增加,故①正确;

②对于多种气体参与反应,反应前后气体的体积不变的反应,并向其中大量加入一种反应物,而使平衡正向移动.生成物的物质的量增加,但百分含量完全可以减小,因为总量多了,故②错误;

③多种物质参加反应,增加一种反应物的浓度,平衡向向正方向移动,提高其它反应物的转化率,自身转化率降低,故③错误;

④多种物质参加反应,增加一种反应物的浓度,平衡向向正方向移动,其它反应物的浓度降低,自身浓度增大,故④错误;

⑤平衡向向正方向移动,正反应速率一定大于逆反应速率,故⑤正确;

⑥使用催化剂不能改变平衡移动,故⑥错误.

故选:①⑤

(4)充入1mol CO2、lmol H2和1mol H2O,反应向逆反应进行建立平衡,等效为(1)中平衡后,再加1molH2O(g),平衡向正反应移动;

令参加反应的H2物质的量为nmol,

              CO(g)+H2O(g)⇌H2(g)+CO2(g),

起始(mol):0         1                 1              1

转化(mol):n         n                 n              n

平衡(mol):n        1+n               1-n            1-n

所以

(1-n)(1-n)
n(1+n)
=4,解得n=0.154

反应前后气体的体积不变,所以平衡时,混合气体的总的物质的量为1mol+1mol+1mol=3mol,

平衡混合物中CO2的体积分数为

1mol-0.154mol
3mol
×100%=28.2%

故答案为:28.2%

多项选择题
单项选择题

As with many a grown-up sporting star, the first hint of greatness came at an early age for Lewis Hamilton. As an eight-year-old at his first kart race, he charged "more like a mature driver than a novice," remembers Martin Hines, owner of the Zip Kart racing company. Scything his way through the field just outside London, Hamilton had a confident style that seemed different from normal rookies, Hines says. "There was a little spark about him." Now 22, and in his debut season in Formula One—he became the first black driver to make it onto the grid in motor racing’s blue-ribbon championship.

His success and profile that have earned young Hamilton comparisons with other sporting greats. His color— Hamilton’s grandfather came to Britain from Grenada in the 50s—and the positive influence of his father, Anthony, have drawn parallels with Tiger Woods. Hamilton acknowledges that his participation could stoke interest among ethnic groups who may not be into the sport now. "Hopefully people that can relate to me will see that it’s possible and also try to get into the sport," he told the BBC. Moreover, his youth, good looks and wholesome image are also likely to get marketers fired up.

Countless more karting titles followed before 2001. He "made seasoned drivers look silly," says Tony Shaw, Hamilton’s then team manager at Manor Motorsport. Hamilton’s raw, natural speed and canny race craft nudged him closer to the big leagues. Hamilton’s "understanding of when and where to overtake and how to take advantage of a situation is very advanced," Shaw says.

At his first crack at GP2, the training ground for Formula One, Hamilton dominated the 2006 season with a series of blistering drives on his way to the title. Hamilton is "not worried about showing or doing what he’s used to doing just because it’s Formula One," says Hill. For many new drivers, "that’s an enormous hurdle." With the retirement last year of seven-time world champion Michael Schumacher, there’s one less rival for Hamilton to negotiate.

And Hamilton is certainly not short on confidence. When he first met Ron Dennis—now his Formula One team boss—as a 10-year-old in a borrowed suit, Hamilton promptly told him he wanted to drive for McLaren. Three years later, he joined the team’s support program for promising young drivers. But, say former team managers, he’s ready to listen and learn when things go wrong. Hamilton has a rare "capacity to question himself—to analyze very clearly after a race," says Frederic Vasseur, general manager at the ART Grand Prix team behind Hamilton’s GP2 championship.

As for whether he’ll become the Tiger Woods of the sport, it’s too early to know whether he can live up to those standards. But for now, his fans are bullish. Damon Hill was the last British driver to take the world crown. And it’s Hamilton, Hill says, "who looks likely to be the next.

Which is the most important reason why Lewis Hamilton "parallels with Tiger Woods"()

A. Both of them first hint their greatness at an early age

B. Hamilton’s grandfather came to Britain from Grenada in the 50s, the positive influence of his father and his color

C. Both of them can get market fire up

D. Both of them have large influence on many kinds of ethnic groups to participate in sports and society