晶体是质点(分子、离子或原子等)在空间有规则地排列,具有规则外形,以多面体出现的

题型:填空题

问题:

晶体是质点(分子、离子或原子等)在空间有规则地排列,具有规则外形,以多面体出现的固体物质。在空间里无限地周期性地重复能形成晶体的、具有代表性的最小单元,称为晶胞。一种Al-Fe合金的立体晶胞如图所示。请据此回答下列问题。

(1)该合金中Fe、A1的原子个数比为____。

(2)若晶体的密度为ρg/cm3,则此合金中最近的两个Fe原子之间的距离(用含ρ的代数式表示,不必化简)为____cm。

(3)取2.78 g该合金粉末溶于100 mL某稀硝酸溶液中,待反应完全后得到1.12 L NO气体(标准状况,且设两者恰好完全反应),则原硝酸溶液的物质的量浓度为______moL/L,反应后溶液中Fe3+的物质的量浓度为__________mol/L。

考点:晶胞
题型:填空题

     Life in the twenty-first century will be very different from life today. Between then and now many

changes will take place, but what will the changes be?

     The population is growing fast. There will be many people in the world and most of them will live

longer than people live now.

     Computers will be much smaller and more useful, and there will be at least one in every home.

And computer studies will be one of the important subjects in schools then.

     People will work fewer hours than they do now and they will have more free time for sports,

watching TV and travelling. Travelling will be much easier and cheaper. And many more people will

go to other countries for holidays.

     There will be changes in our food, too. Maybe no one will eat meat every day, instead they eat

more fruit and vegetables. Maybe people will be healthier.

     Work in the future will be different, too. Dangerous and hard work can be done by robots.

Because of this, many people will not have enough work to do. This will be a problem.

根据短文内容,选择正确答案。

1.There will be _________ in the future.

A. small population

B. few changes

C. more people

D. few people

2.In the future the computer will be _________.

A. much bigger and few people will use it

B. much smaller and more useful

C. smaller and not many people will use it

D. bigger and a lot of people will use it

3.In the future more people _________.

A. will go to other countries for holidays

B. will study at school

C. will go earlier

D. will work for many hours

4.People will prefer _________ to _________ in the future.

A. fruit and vegetables; meat

B. meat; fruit and vegetables

C. fruit and meat; vegetables

D. meat and vegetables; fruit

5. The robots will _________ in the future.

A. do the dangerous work

B. do all the work

C. do only housework

D. do the easy work for people

题型:填空题

短暂性脑缺血发作不正确的是()

A.突然发病

B.可突然跌倒

C.持续时间短暂

D.可眩晕发作

E.恢复后遗留后遗症

题型:填空题

监理工程师对结构物混凝土体积进行计量,应以( )为准。

A.合同图纸净尺寸

B.现场实际测量尺寸

C.与业主协商确定

D.与承包人共同确认

题型:填空题

一辆重为1.5×104N的“东风”牌小汽车,当它以90km/h的速度在水平路面上匀速行驶时,受到的牵引力为2000N,那么汽车发动机的输出功率为         W,重力所做的功为      J。

题型:填空题

温胆汤的君药为

A.半夏
B.竹茹
C.茯苓
D.橘皮
E.枳实

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