问题 问答题

实验室中,常采用分解过氧化氢溶液(二氧化锰作催化剂)或加热高锰酸钾的方法制取氧气.

(1)写出用分解过氧化氢溶液(二氧化锰作催化剂)制取氧气的文字表达式为:______.该反应属于______反应(填“化合”或“分解”)

(2)用过氧化氢分解制取氧气的装置如图所示:图中收集氧气的方法叫做______.可用此方法收集氧气的原因是______.

(3)用该方法收集氧气时,检验集气瓶中氧气是否集满的方法是______.

A、把点燃的木条伸入瓶内

B、把带火星的木条伸入瓶内

C、把带火星的木条放在瓶口

(4)除了用上图方法收集氧气外,实验室还可用______法收集,欲得到较纯净的氧气(尽可能不含空气)最好选用______法收集.收集到气体的集气瓶要______(填“正放”或“倒立”)在桌上.

(5)如果锥形瓶中的反应很剧烈,应该采取的安全措施是______(填编号).

①减慢液体滴加的速度②换用体积较小的锥形瓶③加热锥形.

答案

(1)利用分解过氧化氢制取氧气时,其中的二氧化锰是催化剂,起加快反应速率的作用,是一个反应条件.注意反应物、反应条件及生成物的书写;

(2)因为氧气密度比空气大,故可用向上排空气法收集;

(3)根据氧气具有助燃性,可以使带火星的木条复燃,并且检验集气瓶中氧气是否收集满应该在瓶口检验;

(4)氧气难溶于水,可用排水法收集,欲得到较纯净的氧气,选用排水法收集,氧气密度比空气大,收集满后集气瓶要正放在桌面上;

(5)锥形瓶中的反应如果太剧烈,主要原因就是双氧水的浓度太高,采取安全措施主要考虑这个因素,往锥形瓶中注入少量水,降低过氧化氢的浓度或旋转活塞,减慢液体的滴加速度.

故答案为:

(1)过氧化氢

MnO2
水+氧气;分解;

(2)向上排空气法;密度比空气大;

(3)C;

(4)排水;排水;正立;

(5)①

阅读理解

Twenty–six years after a terrible bicycle accident which left her in a coma(昏迷) for two months and with permanent brain injuries, Barbara Buchan performs many actions more slowly than others. But on September 10 in Beijing, Buchan, at 52, the oldest member of the United States Paralympic team, broke the record and won the gold medal for her disability class in the individual 3,000–meter cycling pursuit.

“You can be very upset at the world and have everyone take care of you.” Buchan said by telephone from Beijing, “or get back on your feet again.”

Buchan first dreamed of Olympic gold at age 15 while watching the 1972 Munich Games. She became a top American cyclist by July 1982, when a terrible road–race crash injured her brain and left doctors doubtful about whether she would survive. She was wearing only a soft leather helmet at the time; her accident made the rule put into practice that cyclists wear the hard–shell helmets that are now common.

Buchan recovered enough of her athletic ability to run track in the 1988 Paralympics in Seoul, where she won a silver medal in the 800 meters. Women’s cycling was not included in the Paralympics yet, so Buchan trained to the point where she raced against men in the 2000 Paralympics in Sydney, Australia-she finished 9th and 10th in two races-and then successfully fought for a separate women’s cycling program beginning in 2004 in Athens, where she did not get a medal.

Even though she was approaching her 50s, Buchan kept racing and again made the United States Paralympic team for Beijing-where she is twice the age of most of her teammates and competitors.

“Barbara’s almost the leader of our team-she’s been through it all,” said Craig Griffin, the United States cycling coach. “She’s never tired. She’s never let her body go and then come back. I don’t think age is as big of a deal as people make it out to be.”

64. According to the text, after the accident,         .

A.Buchan asked her friends to take care of her

B.cyclists started to wear helmets in competition

C.Buchan could not answer questions correctly

D.doctors doubted whether Buchan could come back to life

65. What’s the right order of the events related to Buchan?

a. She won a gold medal in Beijing.

b. She became a top American cyclist.

c. She won a silver medal in the 800 meters.

d. She suffered a terrible bicycle accident.

e. She took part in a cycling program in Athens.

A.c-d-b-a-e               B.b-c-d-a-e 

C.b-d-e-c-a         D.c-b-d-e-a

66. What does the underlined phrase “get back on your feet” in the second paragraph mean?

A.rise to your feet              B.walk on your way

C.go beyond yourself  D.depend on yourself

67. Which of the following can be the best title for this passage?

A.The Making of a Hero     B.From a Loser to a Winner

C.All Roads Lead to Rome  D.Health is Better than Wealth

问答题