问题 多项选择题

微网志的特色在于()

A.简短:不需像部落格般地长篇大论

B.有着MSN的实时性,又没有维护网志的压力

C.接触面广

D.实时:不一定要用计算机,手机也可以

答案

参考答案:A, B, C, D

填空题

下表中列出了一些物质的熔点和沸点(1标准大气圧下),根据表中数据回答下列问题:

物质熔点(℃)沸点(℃)
0100
80210
水银-39357
酒精-11778
-210-196
-268-183
(1)表中所列物质在常温下属于固态的是________;氧在-145℃时所处的状态是______

(2)要探究萘的熔化和沸腾过程中温度的变化,应选_______作温度计的测量物质。

(3)如果在1标准大气压下用降温的办法从空气中提取氧和氮,那么温度下降时首先液化被分离出来的是                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  (4)1标准大气圧下,当温度为0℃时,水的状态(  )

A.一定是固态            B.一定是液态      

C.一定是固液共存态       D.以上三种状态都有可能

判断题