问题 多选题

在一定的条件下,向一密闭的容器内加入化学式为A、B、C、D四种物质各20g,充分反应后,测定其质量,得到数据如下:下列说法不正确的是(  )

物质ABCD
反应前质量(g)20202020
反应后质量(g)2030未知14

A.A物质可能是该反应的催化剂

B.容器内发生了分解反应

C.反应后容器内C的质量为16g

D.容器内发生反应的化学方程式为:2C+3D=5B

答案

A、催化剂能提高化学反应速率,而自身的组成、化学性质和质量在反应前后不发生变化.有图表数据可知,A物质的质量在反应前后没有改变,故可判断A物质可能是该反应的催化剂.故A说法正确;

B、由于CD质量减少,而只有B增加,所以是两种物质生成一种物质,为化合反应.故B说法不正确;

C、根据质量守恒定律,在化学反应中,参加反应前各物质的质量总和等于反应后生成各物质的质量总和.则反应后C物质的质量=20×4-(20+30+14)=16(g);故C说法正确;

D、由图表可知,A物质的质量在反应前后没有改变,说明A没有参与反应.B的质量增加了10g,C质量减少了4g,D质量减少了6g,因为4g+6g=10g,质量比为;4g:6g:10g=2:3:5.但不能说反应为2C+3D=5B.

故选BD.

阅读理解

阅读理解。

     For almost two months Dominic York, a 23-year-old hairdresser, wandered about hospitals

all night, wearing a white coat and pretending he was a doctor. Yesterday he proudly claimed in

court that despite his complete lack of medical experience or qualifications, he had saved several

people's lives. He had even been allowed to assist a surgeon during an emergency operation on a

patient who was about to die on something she had swallowed.

    "I watched one of those TV dramas about a hospital and suddenly I felt like playing one of the

roles myself. So I put on a white jacket and a stethoscope(听诊器)and walked around one of the

biggest hospital in London. At first I just watched. Once you learn how doctors talk to patients,

nurses and others doctors, it's easy to take people in," he said.

    One of the patients he treated was Laura Kennan. She had been knocked down by a car and

fainted. When she came to in hospital, York was standing over her.

    "He looked very professional. He told me his name was Doctor Simon. Then he gave me some

sort of injection," she said. And then he suddenly cleared off when a nurse asked who he was. She

didn't think there was anything wrong. "I would never have realized he was a fake if a policewoman

hadn't showed me his photograph a week later. When the policewoman told me who he really was,

I could hardly believe my cars."

     Judge Raymond Adams told York that he was. " shocked and horrified" that he got away with his

deceiving for so long, and then sentenced him to eighteen months in a special prison for criminal with

mental disorders.

     "I can only hope that this will not lead to further problems. After all, you will have considerable

opportunity to study the behaviour of the psychiatrists(精神科医生)who will look after you while

you are there. If you try to persuade people that you yourself are a psychiatrist after you are set free,

I shall make sure that you are given a much longer sentence." Judge Adams warned York.

1. York was proud of the fact that ___________.

A. a surgeon let him watch an operation.

B. he could perform some duties of a doctor.

C. he had cheated doctors for so long

D. people thought he could become a real doctor

2. York learned how to behave like a doctor by __________.

A. watching other doctors work      

B. talking to doctors and nurses

C. getting some training and experience    

D. observing doctors while he was a patient

3. Why was Laura Kennan in hospital?

A. She had swallowed something and almost died.

B. She had to have and emergency operation.

C. She had been injured in a road accident.

D. She had lost consciousness while driving.

4. The judge's remark implied that York would be more severely punished if he __     _.

A. pretended to be a psychiatrist      

B. tried to get away from prison

C. was proud of what he had done    

D. studied the behaviour of the psychiatrist

单项选择题