问题 选择题

下列有关物质结构中的说法正确的是(    )

A.78g Na2O2晶体中所含阴阳离子个数均为4NA

B.1.5g CH3+中含有的电子数为NA

C.3.4g氨气中含有0.6NA个N—H键

D.PCl3和BCl3分子中所有原子的最外层都达到8电子稳定结构

答案

答案:C

A项,1molNa2O2中含有3mol离子:2mol Na+和1mol O22-,A错;B项,1.5gCH3+的物质的量为0.1mol,1mol的CH3+含有的电子数为8mol,故1.5g CH3+中含有的电子数为0.8NA,B错;C项,3.4g氨气的物质的量为0.2mol,1molNH3所含的N—H键为3mol,故0.2molNH3所含的N—H键为0.6molNA个,C正确;D项,PCl3的分子中,每个原子都达到了8电子稳定结构,而BCl3分子中,氯原子的最外层达到8电子稳定结构,而硼只满足6电子结构,D错。

以阿伏加德罗数为载体考查原子结构及化学键的知识,是历年高考命题的热点题型之一,由此可知:一是应掌握一些常见分子的结构:如1molH2、O2、P4分别含有1molH-H、1molO=O、6molP-P,1molH2O中含有2molO—H、1molNH3含有3molN-H 、1molCH4含有4molC-H、1molSiO2含有4molSi —O。二是要掌握ABn型分子,A、B原子是否满足8电子结构的判断方法是:如果A的化合价的绝对值 + 最外层电子数等于8,即满足8电子结构,否则不满足。

完形填空

完形填空(共20小题,每小题1.5分,满分30分)

阅读下面短文,从短文后所给各题的四处选项(A、B、C和D)中,选出可以填入空白处的最佳选项。

A cat which became famous in Britain for riding on the buses around the southern English city of Plymouth has died after being killed by a car.

Casper, a 12 -year-old black and white cat,   26   leave his house, trotted (慢跑) across the street to the bus stop, queued with bus passengers and'waited for his 27 .He then hopped(跳跃) on the number3 bus to find his  28   seat to curl up on before hopping off at his 29 .The cat was so clever that he knew  30   stop to get off and drivers made sure that he wouldn' t get off at some random(随意的)   31 .Also, the cat seemed to know where to get back  32 , and then he trotted off home.Many local people also knew Casper, who loved everyone and also enjoyed the 33 ourneys, It seemed that 12 -year-old Casper had discovered a very efficient way to 34   the English city of  Plymouth in his golden years.

However, one day ,   35 a motorist hit him and did not stop.Casper was then, in fact, crossing the street to lcatch his usual No.3 bus   36   he was struck by the car.Our friend, Caspar ___37 his injuries.On hearing the news of his death, many people were 38  . A company spokesman said in a statement that Casper _39_ many people' s lives and clearly had a very  40 life traveling around Plymouth.He also suspected that Casper was telling all the other cats in the heaven a bout the many  41_he had experienced. 

Casper' s owner, 55 -year - old Susan Finden, said he had always been a free spirit and was named   42   the cartoon character Casper the Friendly Ghost, because of his habit of 43 off.Finden .posted a sign at Casper' s bus stop to let people know, that they' d no longer be enjoying the company of the cat of whom they'd grown so  44 .

Casper was a special cat and he had a wonderful life.A  45  of the cat will continue to be used on one of the company' s buses. He will be missed for ever.

26.A.used to              B.liked to              C.hated to          D.had to

27.A.time                B.turn                C.place      D.order

28.A.best               B.favpritest             C. most          D.favorite

29.A.destination          B.determination       C.decision              D.description

30.A.where              B.at which             C.what          D.in which

31.A.station            B.stop   C.spot   D.scene

32.A.up                  B.down                C.off      D.on     

33.A.bus                 B.car    C.rail           D.air

34.A.get across           B.get through         C.get down           D.get around

35.A.sadly               B.luckily          C.happily        D.strangely

36.A.while               B.as                 C.when            D.then

37.A.died off               B.died from            C.died down         D.died away

38.A.shocked              B.interested           C.surprised         D.excited

39.A.changed             B.touched            C.turned        D.challenged

40.A.discouraging         B.discouraged         C.excited         D.exciting

41.A.adventures          B.accidents           C.friends        D.incidents

42.A.by                  B.from                C.through             D.after

43.A.wondering            B.wandering          C.cutting             D.going

44.A.familiar             B.similar              C.fond           D.popular

45.A.picture              B.signal               C.movie        D.card

单项选择题