NaCl的晶胞如图，已知钠的相对原子质量为23，氯的相对原子质量为35.5，Na

发布时间：2017-07-20 01:42 │ 来源：www.tikuol.com

题型：计算题

问题：

NaCl的晶胞如图，已知钠的相对原子质量为23，氯的相对原子质量为35.5，Na⁺和C1^-的核间距为a cm，用N_A表示阿伏加德罗常数，则

（1）每个晶胞中平均分摊___个Na⁺，____个Cl^-。

（2）NaCl晶体的密度ρ的表达式为_____ g·cm^-3

考点：晶胞

题型：计算题

完型填空。

     Everyone needs friends. We all like to   1   close to someone.   2   is nice to have a friend to talk, laugh,
and do things with. Certainly, sometimes we need to be alone. We don't always want people   3 . But we
will feel lonely if we   4   have a friend.
     No two people are just the same. Friends   5   don't get on (相处的) well. That doesn't mean that they
no longer like each other. As time passes, they will make up (言归于好) and become   6   again.
     Sometimes friends move away. Then we feel very   7 . We miss them very much, but we can   8   them
and write to them. It is likely that we would never see them again. And we can   9 new friends.
     There's more good news for people who have friends. They live longer than people who don't. Why? It
could be true that they are  10 . Being happy helps you keep healthy.

( )1.A.look
( )2.A.It
( )3.A.alone
( )4.A.ever
( )5.A.always
( )6.A.teachers
( )7.A.angry
( )8.A.call
( )9.A.look for
( )10.A.happier

B. watch
B. He
B. away
B. never
B. sometimes
B. students
B. unhappy
B. ask
B. find
B. poorer

C. feel
C. There
C. all over
C. just
C. often
C. players
C. happy
C. tell
C. make
C. kinder

D. see
D. Someone
D. around
D. really
D. usually
D. friends
D. hungry
D. speak
D. know
D. stronger

查看答案

题型：计算题

X线胸片有偏心空洞，内壁凸凹不平（）

A.肺炎球菌肺炎

B.肺癌

C.葡萄球菌肺炎

D.肺结核

E.肺脓肿

查看答案

题型：计算题

研究工作具有______

A．探索性

B．创造性

C．实用性

D．逻辑性

E．连续性

查看答案

题型：计算题

根据玻尔的氢原子理论，当某个氢原子吸收一个光子后[ ]

A．氢原子所在的能级下降

B．氢原子的电势能增加

C．电子绕核运动的半径减小

D．电子绕核运动的动能增加

查看答案

题型：计算题

手术治疗中一般病人知情权不包括（）

A.有权自主选择

B.有同意的合法权利

C.有明确决定的理解力

D.有家属代为决定的权利

E.有做出决定的认知力

查看答案

更多题库