问题 多选题

在石灰窑中烧制生石灰,1molCaCO3完全分解所需要的能量,可通过完全燃烧0.453mol碳来提供.设空气中O2物质的量分数为0.21,N2为0.79,则石灰窑产生的气体中CO2的物质的量分数可能是(  )

A.0.3

B.0.4

C.0.5

D.0.6

答案

完全燃烧0.453mol碳需要消耗0.453mol氧气(按空气中O2体积分数为0.21)计算,

则至少要空气的量为

0.453
0.21
=2.157摩尔,

其中含氮气的量为:2.157×0.79=1.704摩尔;

  C+O2

 点燃 
.
 
CO2,CaCO3
 高温 
.
 
CaO+CO2 ↑,

  1            1                    1                1

0.453          x                    1               y

由反应方程式可知:完全燃烧0.453mol碳生成 x=0.453mol 二氧化碳;

1mol碳酸钙分解生成  y=1mol 二氧化碳;

石灰窑产生的气体中CO2的体积分数=

1+0.453
1+0.453+1.704
×100%=45.9%≈46%;

这是最大值,如部分生成CO,则二氧化碳体积分数变小;

故选AB.

单项选择题
阅读理解

Louis Pasteur

Louis Pasteur, one of the world's great scientists, was born in 1822, and died in 1895.While still a young boy, Louis Pasteur made his decision to become a scientist. He spent much of his life time studying the diseases of cattle, chickens and other tame animals. His wife learned to help him with his work. Almost everyone knows that Pasteur is the man responsible for finding a way of preventing milk from spoiling (变质). Not many people know he was the first to imagine and to prove that air we breathe is full of germs (细菌).  One of his greatest successes was finding a treatment for people and animals to prevent a disease called rabies (狂犬病). Louis Pasteur won many honors and could have got large amount of money. But Pasteur preferred to live simply. The real happiness of this unusual man came from his work. Louis Pasteur did so well in his life that the French government took up his work and created the Institute Pasteur in the year 1888.

小题1:According to the passage, which of the following statements is true?

A.Pasteur was a scientist and doctor as well.

B.Pasteur lived for less than seventy years.

C.Everybody knows that Pasteur succeeded in finding a way of preventing milk from spoiling.

D.Pasteur's wife was of some help to him in his work.小题2: From the passage, we know that Pasteur lived a simple life. This is because ________.

A.he earned little money.

B.he cared much about money.

C.what he really enjoyed was a simple life.

D.of all mentioned above.小题3:Why were many honors given to Louis Pasteur?

A.Because he was the greatest scientist in the world.

B.Because he spent much of his life time studying the diseases of people.

C.Because he lived simply.

D.Because he was a rare success as a scientist.小题4: Pasteur could have got large amount of money if he had___________.

A.cared much about it.

B.made more discoveries.

C.lived a better life.

D.achieved more successes.小题5:To Louis Pasteur the real happiness in his life was to __________.

A.study

B.work

C.get large amount of money

D.raise tame animals