问题 填空题

利用下图实验装置,按A—B—C顺序连接。可以进行碳及其氧化物的部分性质实验。

(1)实验中A装置处观察到的现象为                                 

(2)实验中正确的接口顺序为a—b—c—          

(3)实验结束应先拔掉C装置上的导管,再熄灭酒精灯。若先熄灭A处酒精灯,则B中

的现象是                                                     

答案

(1)木炭剧烈燃烧,放出大量的热、发出白光                (1分)

(2)e                                                             (1分)

(3)NaOH溶液倒吸入B中,石蕊试纸变成蓝色                        (1分)

(1)氧气通过A装置和木炭加热,两者燃烧反应时观察现象为:木炭剧烈燃烧,放出大量的热、发出白光;

(2)将生成的二氧化碳通过B装置,再通入C装置的氢氧化钠溶液,此时气体应由e管口进入,只有这样才能对二氧化碳进行吸收,否则该实验将无法进行.

(4)实验结束,应先撤离C处导管,再熄灭酒精灯.如果先熄灭A两处酒精灯会导致该装置内温度降低,气压减小,氢氧化钠溶液就会由e管倒吸入B装置内,导致瓶中石蕊试纸变蓝色.

故答案为:

(1)木炭剧烈燃烧,放出大量的热、发出白光;

(2)e;

(3)NaOH溶液倒吸入B中,石蕊试纸变成蓝色.

问答题
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Ask just about any college student you know,and he is likely to tell you that he is a member of facebook.com.Many students say they check their e-mail.It’s so popular “facelooking”has become a verb “Everywhere everyone is doing it,”college student Katie Silverman said,“It’s like everyone’s center of life.”

Facebook is an online social meeting place where students create profiles (简介),share personal information, and meet other members. It is password protected and targeted to high school and college students;members must have an edu.email address to join.

Many students say it has changed their social lives, giving them an easy way to find and chat with classmates who share their interests.“Some people might be too shy to go to talk to someone they like in one of their classes,but on facebook it’s a lot easier to strike up a conversation,”said Rahul Vanjani.

The website was founded by two Harward University students who wanted to meet more of their classmates.It became so popular that the website is at 2,200 colleges and at 22,000 high schools.It says that it has 6 million active users,two—thirds of whom are on it every day.Many of the facebook members said their parents had no idea they were on it .“No way.My parents certainly don’t know about it,” said a college senior who asked us not to use his name.

To keep it popular,Facebook says it stops students posting improper information.Some students have paid the price.At Fisher College in Boston,two students were kicked out for using facebook.com to do something that is against the law.At North Carolina State University,four students were punished for posting photos about drinking.

小题1:The passage is mainly about____.

A.student’s idea about Facebook

B.the development of Facebook

C.the popularity of Facebook with students

D.the rules of Facebook小题2:To become a member of Facebook,you must_____.

A.have an edu,e—mail dress

B.have your own profile

C.be a high school student

D.offer main personal information小题3:By saying “Some students have paid the price”in the last paragraph,the author means more students_____.

A.will have to pay money for being on Facebook

B.always use Facebook to do something against the law

C.have been punished for doing some improper things on Facebook

D.often stop others from posting improper information on Facebook小题4:We can learn about Facebook from the passage that______.

A.the information that students offer to Facebook is secret to others

B.Facebook is at more colleges that at high schools

C.6 million active users of Facebook are on it every day

D.many students don’t want their parents to know they are facebooking