问题 填空题

根据下图所示实验内容回答问题。

(1)仪器①的名称是         

(2)装置Ⅰ用于测定空气中氧气含量,若实验操作规范,该实验得出的结论是         。若实验有误差,下列做法,与误差产生无关的是         (填序号)。

① 红磷不足量            ② 装置气密性不好

③弹簧夹没有加紧        ④ 利用热铜丝点燃红磷

(3)装置Ⅱ用于高锰酸钾制氧气,反应的化学方程式为         ,当气体收集满后,有下列操作① 将导气管移出集气瓶口;②取出集气瓶,正放在桌面上;③盖上玻璃片;④将集气瓶和玻璃片一起取出,正放在桌上;⑤在水面下用玻璃片盖住集气瓶口;⑥把导管从水槽中拿出来;⑦熄灭酒精灯,正确的操作及顺序是        (填字母)。

A.①②③⑥⑦

B.①②③⑦⑥

C.①⑤④⑥⑦

D.①⑤④⑦⑥

答案

(1)集气瓶

(2)空气中氧气约占总体积的五分之一 ;④

(3)2KMnO4K2MnO4+MnO2+O2↑ ;C

分析:(1)根据仪器的图形和用途确定名称;

(2)根据实验室测定空气中氧气含量的实验结论和注意事项分析;

(3)根据实验室正确氧气的反应原理和步骤回答.

解答:解:(1)仪器①是用来收集气体的,其名称是集气瓶.

(2)根据氧气在空气中的体积分数,该实验可得出的结论是空气中氧气约占总体积的五分之一.若实验有误差,下列做法,与误差产生无关的是利用热铜丝点燃红磷;

(3)高锰酸钾制氧气的化学方程式为2KMnO4K2MnO4+MnO2+O2↑,当气体收集满后,要注意先撤导管,再熄灭酒精灯;

故答案为:(1)集气瓶

(2)空气中氧气约占总体积的五分之一;④

(3)2KMnO4K2MnO4+MnO2+O2↑C

阅读理解

Passage 3

Are you looking for something fun and would you like to help others in your spare time? Then join us to be a volunteer! We’re a non-profit (赢利的) organization. We have volunteer jobs of all ages. Anyone, from twelve-year-old children to people in their seventies can become a volunteer.

You can help people in many ways. Schools need help with taking care of children while parents are working. Hospitals need volunteers to look after children while their parents are seeing a doctor. Animal lovers can help take care of those dogs and cats without homes. There is something for everyone.

“As a volunteer, I don’t want to get anything. Seeing the children’s happy faces, I’m happy, too.” Said Carlos Domingo, an old woman of 62. “I often played computer games in my spare time before. Now I help older people learn how to use computers.” said another volunteer at the age of 18.

If everyone helps out a bit, we’ll have a better world to live in. Interested? Call us 1-800-555-5756 or visit our website: www.activol.com.

小题1:When do the volunteers help others?

A.In their spare time.

B.At weekends

C.On weekdays.

D.In the evenings.小题2:_____ can be a volunteer.

A.Children

B.Old women

C.Anyone aged 12-70

D.Young people小题3:Volunteers want to get _______ when they help others.

A.money

B.computers

C.everything

D.nothing小题4:Carlos Domingo does volunteer work with ______.

A.animals

B.children

C.computers

D.older people小题5:We can read such a passage ______.

A.in a newspaper

B.in a storybook

C.in a picture book

D.in a textbook

多项选择题