问题 填空题

研究NO2、SO2、等大气污染气体的处理具有重要意义.

(1)NO2可用水吸收,相应的化学反应方程式为______.利用反应6NO2+8NH3

催化剂
加热
7N2+12H2O也可处理NO2.当转移1.2mol电子时,消耗的NO2在标准状况下是______L.

(2)已知:2SO2(g)+O2(g)⇌2SO3(g)△H=-196.6kJ•mol-1

2NO(g)+O2(g)⇌2NO2(g)△H=-113.0kJ•mol-1

则反应NO2(g)+SO2(g)⇌SO3(g)+NO(g)的△H=______kJ•mol-1

一定条件下,将NO2与SO2以体积比1:2置于密闭容器中发生上述反应,下列能说明反应达到平衡状态的是______.

a.体系压强保持不变b.混合气体颜色保持不变

c.SO3和NO的体积比保持不变d.每消耗1molSO3的同时生成1molNO2

测得上述反应平衡时NO2与SO2体积比为1:6,则平衡常数K=______.

答案

(1)NO2与H2O反应的方程式为:3NO2+H2O═2HNO3+NO;6NO2+8NH3═7N2+12H2O,当反应中有1 mol NO2参加反应时,共转移了4 mol电子,故转移1.2mol电子时,消耗的NO2为1.2×

1
4
×22.4L=6.72L,故答案为:3NO2+H2O=NO+2HNO3;6.72;

(2)根据盖斯定律,将第二个方程式颠倒过来,与第一个方程式相加得:2NO2+2SO2═2SO3+2NO,△H=-83.6 kJ•mol-1,则NO2+SO2⇌SO3+NO,△H=-41.8 kJ•mol-1

本反应是反应前后气体分子数不变的反应,故体系的压强保持不变,故a不能说明反应已达到平衡状态;随着反应的进行,NO2的浓度减小,颜色变浅,故b可以说明反应已达平衡;SO3和NO都是生成物,比例保持1:1,故c不能作为平衡状态的判断依据;d中所述的两个速率都是逆反应速率,不能作为平衡状态的判断依据,故选c;

NO2(g)+SO2(g)SO3(g)+NO(g)

起始物质的体积 1a 2a 0 0

转化物质的体积 x x x x

平衡物质的体积 1a-x 2a-xxx

则(1a-x):(2a-x)=1:6,故x=

4
5
a,故平衡常数为=x2/(1a-x)(2a-x)=
8
3

故答案为:-41.8;b;

8
3

阅读理解

For years I wanted a garden. I’d spend hours thinking of different things I could plant that would look nice together.

But then we had Matthew, and Marvin, and the twins Alisa and Alan, and then Helen. I was too busy raising them to grow a garden.

Money was not enough. Neither was time. Often when my children were little,one of them would want something that cost too much, and I’d have to say, “Do you see a money tree outside? Money doesn't grow on trees, you know.”

Finally, all the children got through high school and college and were off on their own. I started thinking again about a garden.

Then, one spring morning, on Mother’s Day, I was working in my kitchen. Suddenly, I looked out of the window and there was a new tree, planted right in my yard. There were things blowing around on it. Then I put my glasses on—and I couldn’t believe what I saw.

There was a money tree in my yard!

I went outside to look. It was true! There were dollar bills*, one hundred of them, hanging all over that tree. There was also a note among them, “Thank you for your time, Mom. We love you!”

Later, my children bought me tools, ornaments, a sunflower stepping stone and gardening books. A new page started in my life.

That was three years ago. My garden’s now very pretty, just like I wanted. When I go out and take care of my flowers, I don’t seem to miss my children as much as I once did. It feels like they’re right there with me. Now every year when winter comes, I look out of my window and think of the flowers I’ll see next spring in my little garden. I think about what my children did for me, and I get tears in my eyes—every time.

I’m still not sure that money grows on trees. But I know love does!

小题1:How many children did the writer have?

A.Three

B.Four

C.Five

D.Six小题2: What did the mother mean when she said “Money doesn’t grow on trees”?

A.She was too busy to plant a money tree at that time.

B.She had to save money so that she could have a garden.

C.It wasn’t easy for her to make money to raise all the children.

D.They didn’t have much money because the mother lost her job.小题3: The “money tree” appeared in the writer’s yard _________.

A.before her children were born

B.one spring morning when the children were little

C.after the children went to school

D.on a Mother’s Day after the children left her小题4: The children planted a money tree in their mother’s yard because _________.

A.their mother needed money badly

B.they wanted to show their love to their mother

C.it was time for them to give the money back to her

D.they wanted to live together with their mother forever

单项选择题