问题 填空题

(12分)氨是氮循环过程中的重要物质,氨的合成是目前普遍使用的人工固氮方法。合成氨反应:N2(g)+3H2(g)2NH3(g)△H

(1)若该反应在一定条件下能自发,则该反应的△H   0、△S    0(填“<”、“>”或“=”)。

(2)在恒容容器中,下列描述中能说明上述反应已达平衡的是        

A.3v(H2)=2v(NH3)

B.单位时间内生成n mol N2的同时生成2n molNH3

C.混合气体的密度不再改变

D.容器内压强不随时间的变化而变化(3)一定温度下,向2L密闭容器中充入1molN2和3molH2,保持体积不变,0.5min后达到平衡,测得容器中有0.4mol NH3,则平均反应速率v(N2)=          ,该温度下的平衡常数K=           。若升高温度,K值变化     (填“增大”、“减小”或“不变”)。

(4)为了寻找合成NH3的温度和压强的适宜条件,某同学设计了三组实验,部分实验条件已经填在下面实验设计表中。请在下表的①②处填入合适的实验条件数据。

实验编号T(℃)n (N2)/n(H2)P(MPa)平衡时NH3百分含量
4501/31 
1/3 
4801/310 

答案

(1)  < ,<  (每空1分) (2)    BD     (2分)

(3) 0.2mol/(L· min)    、     0.058        、  减小  (每空2分)

(4)①     450(或480)      、②  10(或1)      。(每空1分)

(1)根据方程式可知△S<,又因为反应是自发的,所以△H<0。

(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。A中反应速率的方向相反,但满足速率之比是相应的化学计量数之比,不正确。B中反应速率的方向相反,且满足速率之比是相应的化学计量数之比,正确。反应前后体积减小,所以压强也是减小的,D可以说明。密度是混合气的质量和容器容积的比值,在反应过程中质量和容积始终是不变的,C不正确。答案选BD。

(3)容器中有0.4mol NH3,则消耗氮气是0.2mol,所以其反应速率是0.2mol÷2L÷0.5min=0.2mol/(L·min)。平衡时氢气、氮气、氨气的浓度分别是1.2mol/L、0.4mol/L、0.2mol/L,所以平衡常数K=。正反应是放热反应,升高温度,平衡向逆反应方向移动,平衡常数减小。

(1)如果实验①②中温度相同,则压强就不同,反之亦然,同样实验②③中压强相同,温度就不同,反之亦然。

阅读理解

阅读理解。

     Mr. and Mrs.Turner live outside a small town.They have a big farm and they are always busy working on it. Their son, Peter, studied at a middle school. The young man studied hard and did well in his lessons. It made them happy.

     Last month Peter finished middle school and passed the entrance examination (升学考试).Mrs.Turner was very happy and told the farmers about it.

     Yesterday morning the woman went to the town to buy something for her son. On the bus she told one of her friends how clever and able her son was. She spoke very loudly. All the people in the bus began to

listen to her.

     "Which university (大学) will your son study in?" a woman next to her asked.

     "In the most famous university in our country!" Mrs. Turner said happily.

     "The most famous university?""Oxford University (牛津)."

     Most of the passengers (乘客) looked at her carefully. Some of them said to her, "Congratulations!"

A woman said, "I'm sure he'll know Fred Smith.""Who's Fred Smith?""He's my son." "Does he study in

the university, too?" "No, "said the woman. "He is one of the professors."

l. The story happened in _______.

A. America

B. France

C. Germany

D. England

2. Mr. and Mrs. Turner were happy because _______.

A. their son did well in his lessons

B. they have a big farm

C. they have a good harvest

D. their son studied at a middle school

3. Mrs. Turner wanted everyone to know _______.

A. her son finished middle school

B. her son was handsome

C. her son was going to study in a university

D. her son was very friendly to others

4. Mrs. Turner spoke so loudly in the bus that _______.

A. her friend could hear her

B. all the people could hear her

C. she hoped to make all the people happy

D. she hoped they would say congratulations to her

5. Which of the following is true? _______.

A. The woman wasn't interested in Mrs. Turner's words

B. Mrs. Turner knew nothing about the famous university

C. The woman wanted to stop Mrs. Turner from showing off (炫耀)

D. The woman next to Mrs. Turner wanted to show off her son, too

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