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问题 选择题

下列叙述中完全正确的一组是（　　）

①常温常压下，1mol甲基（-CH3）所含的电子数为10NA

②由Cu、Zn和稀硫酸组成的原电池工作时，若Cu极生成0.2gH2，则电路通过电子0.2NA

③在标准状况下，11.2L NO与11.2L O2混合后气体分子数为0.75NA

④常温常压下，16g O3所含的原子数为NA

⑤1mol C10H22分子中共价键总数为31NA

⑥1mol Cl2发生反应时，转移的电子数一定是2NA

⑦标准状况下，22.4L水中含分子数为NA．

A．①②③④⑤

B．②④⑤⑥⑦

C．②④⑤

D．①②⑤

答案

①甲基是甲烷失去一个H原子后剩余的部分，所以一个甲基中的电子数是9，则1mol甲基（一CH3）所含的电子数应为9NA，故①错误；

②铜锌原电池中正极上生成0.1molH2，需得到0.2mol电子，所以电路中通过的电子也是0.2NA，故②正确； 

③NO与O2在标况下反应生成NO2，根据反应的化学方程式可以计算出生成的NO2为0.5mol，剩余的O2为0.25mol，即气体的总的物质的量为0.75mol，但NO2还有一个平衡：2NO2⇌N2O4，而此平衡的存在就使气体的总的分子数小于0.75mol，故③错误；

④O3是氧的单质，所以16gO3中所含只有氧原子，氧原子个数为：N=nNA=

m
M
NA=
16g
16g/mol×3
×3=NA，故④正确；

⑤甲烷分子中的共价键数为4，乙烷为7，丙烷为10，以此类推，可知含有10个碳原子的烷烃其中所含的共价数为3×10+1=31，故⑤正确；

⑥氯气只作氧化剂时，1 mol Cl2发生反应，转移的电子为2mol，但在发生歧化反应时，情况就有所不同了，例如，氯气与水反应时，1 mol Cl2发生反应时，转移的电子为1mol，故⑥错误；

⑦标准状况下，水呈液态，故22.4L的水并不是1mol，故⑦错误．

故选：C．

单项选择题

The Lake District in north-west England is an area remarkably little affected by industrialization. The principal activity is still sheep-farming, as it has been for a thousand years, and many ancient words like "fell" for "hill" and "tam" for "lake" are still in daily use. In spite of its heavy rainfall and relative inaccessibility, its special atmosphere and spectacular natural beauty combine to make this one of England’s favourite holiday areas at all seasons of the year. But at Christmas 1968, still gripped by the fear that foot-and-mouth disease could spread to the hill flocks and sweep like wildfire right up to the Scottish border, it was quieter than ever before in this century. Luckily not a single farm had caught tile infection, the nearest case having been an isolated one at Kendal several weeks before. But every Lakeland farmer knows that one case among the unfenced hill flocks on the fells could lead to complete annihilation of hundreds of thousands of sheep and the virtual end of the district’s principal industry; you cannot replace sheep, acclimatized to their own part of the fell for generations, in the same way that you can replace cattle in a field.
Nobody could remember a Christmas like it, especially Boxing Dab, which is traditionally one of the big outdoor holidays of the Lakeland year. Normally this is a day spent following the mountain packs of hounds, fell-walking and, if the weather is propitious, skiing and skating, but this time there were none of these things. Visitors were actively discouraged, and those who did come were asked not to go on the fells, footpaths or bridleways or near farmland, while motorists were requested not to drive on minor roads and to shun the smaller valleys. The enterprising hotels which had earlier in the year decided to keep open during the winter were by the end of October having a desperate time. Hundreds of bookings had been cancelled and scores of dinner parties and young farmers’ reunions eliminated. All youth hostels were closed. At least one climbing club, unable to climb, substituted a training programme of films and simulated climbs on the more substantial municipal buildings.
The weather in the area was dry, crisp, windless and cold, in fact ideal for brisk outdoor activities. But nobody was able to enjoy it. Everything was stopped: hunting, walking, climbing, skiing, motor cycle trials, sporting events of every description. All the seasonal dances, festivals, conferences, shepherds’ meets and a hundred and one, other social occasions abandoned. The ice was bearing on some of the lakes but you could not go skating there. Meanwhile the foxes, emboldened by an unprecedented freedom from harassment, were stalking closer to the farms and the flocks of Christmas turkeys, while the hounds sulked miserably in their kennels.
Farmers are apt to criticize some sections of the outdoor fraternity for their occasional thoughtless behaviour, but the way that walkers, climbers, skiers, fishermen, hunters and the rest went out of their way to help them at this time should never be forgotten. The general public, locals and visitors alike, tried to give the fell farmers a sporting chance, and this remarkable display of public spirit was the one bright note in a very sad time.

The word "this" in line 5 refers to______.

A．(A) its special atmosphere

B．(B) the Industrial Revolution

C．(C) the spectacular natural beauty

D．(D) the Lake District
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单项选择题

某电机槽绝缘为聚酰亚胺薄膜，浸漆处理时采用1053有机硅绝缘漆，则该部件经处理后的耐热等级为（）级。

A.B

B.F

C.H

D.C
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