问题 计算题

(8分)150 ℃、101 kPa时,由两种烃组成的混合气体0.5 L在4.5 LO2(足量)中完全燃烧,测得反应后气体总体积小于5 L,其中含CO2 0.8 L。

(1)求此混合气体中两种烃的分子式。

(2)求此混合气体中两种烃的体积比。

(3)求生成水蒸汽的体积。

答案

(8分)

因为反应前后气体体积缩小,所以H的平均数小于4,则气体中一定含有C2H2;又因为混合气体0.5L燃烧后生成0.8LCO2,所以C的平均数为1.6,则一定含有CH4

1               0.4

1.6

2               0.6

所以体积比n(CH4):n(C2H2)=2:3

根据H守恒,V(H2O)="0.4+0.3=0.7" L

阅读理解

Reading comprehension.

     Stephen Hawking was born in Oxford, England, in 1942. He went to school in St Albans. After leaving

school, Hawking went first to Oxford University where he studied physics, then he went on studying in

Cambridge University. As he himself admits (承认), he didn't work hard. He was a lazy student, and did

very little work. However, he still got good marks.

     At the age of 20, he first noticed something was wrong with him. His mother was very worried and

took him to see a doctor. He was sent to hospital for tests. He had an incurable (不可治愈的) illness. And

the doctor said he would die before he was 23.

     At first, he became very sad and disappointed (失望的). After coming out of the hospital, he suddenly

realized that life was beautiful. Later he married, found a job and had three children. He also went on with

some of the most important scientific research.

     Today, Hawking still works at Cambridge University as a professor. He strongly believes that his story

shows that nobody, however bad their situation is, should lose hope. "Life is not fair," he once said, "You

just have to do the best you can in your own situation."

Judge the following sentences true (T) or false (F) according to the passage.

( )1. As a university student, Stephen Hawking worked very hard.

( )2. Stephen Hawking first noticed something was wrong with him when he was 23.

( )3. Hawking changed his life attitude (态度) after he had come out of the hospital.

( )4. There were three people in Hawking's family.

( )5. From the passage, we know that we shouldn't lose hope in our bad situation.

多项选择题