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问题 选择题

设氯原子的质量为ag，12C原子的质量为bg，用NA表示阿伏加德罗常数的值，则下列说法正确的是……（ ）

A．氯元素的相对原子质量为12/b

B．mg该氯原子的物质的量为m/(aNA) mol

C．该氯原子的摩尔质量是aNAg

D．ng该氯原子所含的电子数是17n/a

答案

BD

该题考查相对原子质量、物质的量、摩尔质量等概念，要通过它们之间的联系进行解答。

A、错误，元素的相对原子质量是各同位素的平均值

B、正确，一个该氯原子的质量是a，则1mol该氯原子的质量(摩尔质量)为aNA，那么mg该氯原子的物质的量即为m/aNAmol

C、单位错误

D、正确，ng/ag即为ng该氯原子所包含的该氯原子的个数，每个该氯原子含电子17，则ng该氯原子所含电子为17×n/a

填空题

一个地区的人口自然增长率由______和______决定．
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完形填空
完形填空。

      An English padre(神父) wanted to become a member of a certain club in Africa.In order to
become a member,each person had to __1__ at least one lion.The padre had never shot an
animal for his life.So,armed with a rifle and led by a young African boy,the padre set out one
evening for a pool in the jungle where he was told a lion came each evening to __2__.He waited
patiently for a few __3__until shortly before midnight when he heard a rustling(沙沙声) noise.
Sure enough a few feet away the head of the lion appeared above a bush that separated the
padre and the pool.He aimed and fired.The head of the lion__4__fell behind the bush but a
moment later __5__.So the padre aimed and __6__again.The head of the lion fell behind the
bush and once more reappeared.The padre fired again: the same __7__.He remained calm
because he __8__he had brought sixteen bullets with him.After his fourth try,his aim seemed
to become more and more __9__: in fact,after his __10__ try the African boy had to __11__
him:"This is your last chance.If you __12__ this time,we are in trouble." The padre then realized
how __13__the situation was,so he took a deep breath,aimed very carefully and fired.They
waited for a moment,and then slowly __14__ up to twenty: the head of the lion did not
reappear.The padre was certain that at last he had shot his lion.They __15__ forward together
to the spot behind the bush.And what do you think they found? Sixteen lions!

( )1．A.shoot
( )2．A.eat
( )3．A.minutes
( )4．A.fast
( )5．A.turned
( )6．A.killed
( )7．A.result
( )8．A.acknowledged
( )9．A.inaccurate
( )10．A.last
( )11．A.tell
( )12．A.fell
( )13．A.difficult
( )14．A.counted
( )15．A.drove

B ．kill
B ．walk
B ．seconds
B ．immediately
B ．reappeared
B ．jumped
B ．situation
B ．understood
B ．unnecessary
B ．fifteenth
B ．frighten
B ．shot
B ．serious
B ．waited
B ．rushed

C．catch
C．drink
C．days
C．once
C．returned
C．fired
C．answer
C．believed
C．impossible
C．sixteenth
C．warn
C．fired
C．exciting
C．added
C．wandered

D．hurt
D．hunt
D．hours
D．directly
D．moved
D．tied
D．problem
D．knew
D．indirect
D．many
D．remain
D．missed
D．mad
D．named
D．climbed
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