问题 填空题

(11分)

(Ⅰ)有可逆反应A(g) + 3B(g)   2C(g) △H<0

(1)已知该反应的平衡常数表达式:K=[C]2/[A][B];升高温度,平衡常数K将_______________(填“增大”,“减小”,“不变” )。([X]表示相应物质的浓度)

(2)一定条件下,该反应达平衡后,保持其他条件不变,再充入C气体,20 min后又达新平衡。试推测,与原平衡状态相比,第15 min时,V正_______(填“增大”,“减小”,“不变” ),V逆______(填“增大”,“减小”,“不变” )。

(3)该反应的速率与时间的关系如下图所示:

可见在t1、t3、t5、t7时反应都达到平衡,如果t2、t4、t6、t8时都只改变了一个反应条件,请指出改变了什么条件(例如:减小生成物的浓度)

t2时_________    ___;t4时______ _____;t6时___  _______;t8时_______ ____。

(Ⅱ)、一定温度下在体积为5 L的密闭容器中发生可逆反应。

若某可逆反应的化学平衡常数表达式为

(1)写出该反应的化学方程式:                                   

(2)能判断该反应一定达到化学平衡状态的依据是       (填选项编号)。

A.容器中气体的平均相对分子质量不随时间而变化

B.υ(H2O)=υ(H2)

C.容器中气体的密度不随时间而变化

D.容器中总的物质的量不随时间而变化E. 消耗n mol H2的同时消耗n mol CO

答案

(1)    减小(1分)    (2)增大    增大   (2分)

(3)升高温度   减小压强   增大反应物浓度  使用了催化剂  (4分)

(Ⅱ)(1)(2)

(Ⅰ)(1)反应是放热反应,所以升高温度平衡向逆反应方向移动,平衡常数减小。

(2)增大生成物浓度,正逆反应速率都是增大的。

(3)t2时正逆反应速率都是增大的,但平衡向逆反应方向移动,所以改变的条件是升高温度。t4时正逆反应速率都是减小的,但平衡向逆反应方向移动,所以改变的条件是减小压强;t6时正反应速率增大,逆反应速率不变,平衡向正反应方向移动,所以改变的条件是增大反应物浓度;t8时,正逆反应速率都是增大的,但平衡不移动,所以改变的条件是使用了催化剂,

(Ⅱ)(1)根据平衡常数的表达式可知,方程式为C+H2O(g)H2+CO。

(2)在一定条件下,当可逆反应的正反应速率和逆反应速率相等时(但不为0),反应体系中各种物质的浓度或含量不再发生变化的状态,称为化学平衡状态,所以B正确。E中反应速率的方向是相同的,不正确。反应前后条件减小,所以压强也是减小的,D正确。密度是混合气的质量和容器容积的比值,在反应过程中容积始终是不变的,但质量是变化的,所以C正确。混合气的平均相对分子质量是混合气的质量和混合气的总的物质的量的比值,质量和物质的量都是变化的,所以A可以说明。答案选ABCD。

多项选择题
阅读理解

D

For John and Amy Cervantes, birthdays have always been a big deal — a welcome excuse to celebrate life. When their eldest son, Alex, turned three, in 2005, they invited 20 friends to a nearby park and hired a clown to paint faces and make balloon animals.

Not long after that, the couple were brainstorming ways to teach Alex about giving to others. “That’ s when a spark went off,” says Amy. “We wanted to do something that would have a strong effect on our community, that wasn’t already being  done, and that our young children could participate in. I started wondering what less fortunate kids do on their birthdays. The next day, we called a local shelter.” What they learned is that homeless children typically don’t do anything to celebrate. No cake. No gifts. No party.

Several weeks later, the family threw a party at the shelter for the children who had birthdays that month. They decorated, served cake, and led 50 kids in the uncertain situation. Alex helped fill and pass out goody bags and presents. Since that first party, the couple have turned their simple idea into Birthday Blessings, a nonprofit that hosts monthly parties at ten shelters in and around Charlotte, North Carolina. The group also delivers baby supplies to new moms in the shelters. And it considerately sends treats to elementary schools so homeless kids can celebrate their birthdays with friends.

To date, Birthday Blessings has thrown more than 500 parties and handed out over 22,000 favors to nearly 4,000 homeless children. The idea is spreading fast, with additional chapters set to start in Atlanta, Cincinnati, and northeast Indiana. Birthday Blessings is operated entirely by volunteers with Amy, a stay-at-home mom, in charge. John attempts his career as an investment adviser while setting up the group’s similar network and running its capital campaign. The charity will take almost anything — toys, baby items — as long as it’s not used. “These kids never get anything new,” John says. “It makes a big difference to them psychologically.”

Being part of this“labor of love,” as Amy puts it, is already making an impression on the boys. When Alex turned seven, his grandparents sent a birthday check. “The first thing he said when he opened it,” Amy recalls, “was that he wanted to give half to the birthday kids.”

63. “a spark went off,” in Para 2 is closest in meaning to_______ .

A. Something was burning        B. there was a little hope

C. they were excited.            D. some good idea flashed into their mind.

64. The couple held a party at the shelter because_____ .

A. The children had birthdays that month

B. They felt sympathy for the homeless children

C. They wanted to make good impression on the children

D. They wanted to show that they were generous and kind

65. From the passage we can learn_______ .

A. The homeless children typically receive gifts and eat cakes on their birthdays

B. The group carefully sends treats to all the children in elementary schools

C. Birthday Blessings has performed different activities to aid the homeless children.

D. The couple are responsible for their own community in North Carolina

66. Which would be the best title for the passage?

A. Labor of Love                B. Nonprofit Organization 

C. Warm-hearted Volunteers.      D. Fortunate Children