问题 问答题

过渡排放CO2会造成“温室效应”,科学家正在研究如何将CO2转化为可利用的资源.其中一种方案就是将CO2转化为可再生燃料甲醇(CH3OH).其化学方程式为:

请填空:

(1)写出上述反应的平衡常数表达式______:

(2)在容积为2L的密闭容器中,用一定量的二氧化碳和一定量氢气在一定条件下合成甲醇,实验结果如图所示.下列说法正确的是______(填序号)

A.在300℃,从反应开始到平衡,甲醇的平均反应速率v(CH3OH)=

nA
tA
mol•(L•min)-1

B.反应体系从300℃升温到500℃,平衡常数K变化大

C.该反应的正反应为放热反应

D.处于C点的反应体系从300℃升高到500℃,

n(H2)
n(CH3OH)
增大

(3)25℃,1.01×105Pa时,16g 液态甲醇完全燃烧,当恢复到原状态时,放出369.2kJ的热量,该反应的热化学方程式为:______.

(4)选用合适的合金为电极,以氢氧化钠、甲醇、水、氧气为原料,可以制成一种以甲醇为原料的燃料电池,此电池的负极应加入或通入的物质是______;正极的电极反应式:______.

答案

(1)根据K=生成物的浓度幂之积除以反应物的浓度幂之积,得出K=

c(CH3OH)•c(H2O)
c(CO2)•c3(H2)
,故答案为:K=
c(CH3OH)•c(H2O)
c(CO2)•c3(H2)

(2)A、化学反应速率等于单位时间内物质浓度的变化量,甲醇的平均反应速率v(CH3OH)=

nA
2
tA
mol•(L•min)-1,故A错误;

B、根据图示信息:升高温度,甲醇的物质的量减少,所以反应逆向进行,即反应是放热反应,对于放热反应,升高温度,平衡常数减小,故B错误;

C、根据图示信息:升高温度,甲醇的物质的量减少,所以反应逆向进行,即反应是放热反应,故C正确;

D、C点时反应达到平衡状态,升高温度,对于该放热反应,平衡逆向进行,所以

n(H2)
n(CH3OH)
增大,故D正确;

故选CD.

(3)16g 液态甲醇完全燃烧,当恢复到原状态时,放出369.2kJ的热量,则1mol 液态甲醇完全燃烧,当恢复到原状态时,放出725.8kJ的热量,即热化学方程式为:

CH3OH(l)+

3
2
 O2=CO2(g)+2H2O(l)△H=-725.8kJ/mol,故答案为:CH3OH(l)+
3
2
 O2=CO2(g)+2H2O(l)△H=-725.8kJ/mol;

(4)甲醇为原料的燃料电池中,燃料甲醇为负极,发生失电子的氧化反应,氧气是正极,发生得电子得还原反应,根据所给试剂,只能选择氢氧化钠为电解质,在碱性环境下,氧气的放电情况为:O2+2H2O+4e-=4OH-,故答案为:甲醇;O2+2H2O+4e-=4OH-

阅读理解

I began working in journalism(新闻工作)when I was eight. It was my mother’s idea. She wanted me to “make something” of myself, and decided I had better start young if I was to have any chance of keeping up with the competition.

With my load of magazines I headed toward Belleville Avenue. The crowds were there. There were two gas stations on the corner of Belleville and Union. For several hours I made myself highly visible, making sure everyone could see me and the heavy black letters on the bag that said THE SATURDAY EVENING POST. When it was suppertime, I walked back home.

“ How many did you sell, my boy?” my mother asked.

“ None.”

“ Where did you go?”

“ The corner of Belleville and Union Avenues.”

“ What did you do?”

“ Stood on the corner waiting for somebody to buy a Saturday Evening Post.”

“ You just stood there?”

“ Didn’t sell a single one.”

“ My God, Russell!”

Uncle Allen put in, “ Well, I’ve decided to take the Post.” I handed him a copy and he paid me a nickle(五分镍币). It was the first nickle I earned.

Afterwards my mother taught me how to be a salesman. I would have to ring doorbells, address adults with self-confidence(自信), and persuade them by saying that no one, no matter how poor, could afford to be without the Saturday Evening Post in the home.

One day, I told my mother I’d changed my mind. I didn’t want to make a success in the magazine business.

“ If you think you can change your mind like this,” she replied, “ you’ll become a good-for-nothing.” She insisted that, as soon as school was over, I should start ringing doorbells, selling magazines. Whenever I said no, she would scold me.

My mother and I had fought this battle almost as long as I could remember. My mother, dissatisfied with my father’s plain workman’s life, determined that I would not grow up like him and his people. But never did she expect that, forty years later, such a successful journalist as me would go back to her husband’s people for true life and love.

小题1:Why did the boy start his job young?

A.He wanted to be famous in the future.

B.The job was quite easy for him.

C.His mother had high hopes for him.

D.The competiton for the job was fierce.小题2:From the dialogue between the boy and his mother, we learn that the mother was _______.

A.excited

B.interested

C.ashamed

D.disappointed(失望的)小题3:What did the mother do when the boy wanted to give up?

A.She forced him to continue.

B.She punished him.

C.She gave him some money.

D.She changed her plan.小题4:What does the underlined phrase “this battle”(last paragraph) refer to?

A.The war between the boy’s parents. 

B.The arguing between the boy and his mother.

C.The quarrel between the boy and his customers. 

D.The fight between the boy and his father.小题5:What is the text mainly about?

A.The early life of a journalist.

B.The early success of a journalist.

C.The happy childhood of the writer.

D.The important role of the writer in his family.

单项选择题