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小明同学课下自制了如图的实验装置，对水通电分解进行了实验探究，请你和他一起完成此实验．

通电一段时间后，在两个试管中分别收集到两种气体．请回答：

（1）气体a为______，它连接的是电源的______极．

（2）如何检验左侧试管中的气体______．

（3）该反应的文字表达式是______．

（4）从图中可知a气体的一点物理性质是______．

（5）小红同学对纯净的氢气在空气中燃烧进行了实验探究，请你帮她完成下表：

实验步骤实验现象实验结论备注
①点燃纯净的氢气发出______火焰．反应的文字表达

式是______

②______．______有水生成
③用手轻轻触摸烧杯．______说明此反应中伴随能量变化，把______能转变成了______能．
（6）以氢燃料电池为动力的客车运行过程中，不排放任何有害气体，称为“零排放”汽车．其原因是______．

①氢气比空气轻②氢气有广泛的来源③氢气燃烧时放热多④氢气燃烧只生成水．

答案

（1）由图可知a与电源负极相连，与负极相连的是氢气；

（2）左侧试管中的气体是氧气，检验氧气用带火星的木条，方法是：将试管取出倒转，用带火星的木条迅速放到试管口，该气体能使带火星的木条复燃；

（3）水在通电的条件下生成氢气和氧气，反应的文字表达式为：水

通电
氢气+氧气

（4）氢气的物理性质有：无色无味，难溶于水的气体，密度比空气的小；

（5）纯净的氢气在空气中燃烧发出淡蓝色的火焰，在火焰的上方罩一个干而冷的烧杯，烧杯内有水雾出现，可得出氢气燃烧有水生成；

用水摸烧杯的壁，烧杯比发烫，说明此反应中伴随能量变化，把化学能变为了热能，反应的文字表达式为：水

通电
氢气+氧气

（6）因为氢气的燃烧产物为水，故不排放任何有害气体，称为“零排放”汽车．

故答案为：（1）氢气负极

（2）将试管取出倒转，用带火星的木条迅速放到试管口，该气体能使带火星的木条复燃．

（3）水

通电
氢气+氧气

（4）难溶于水或密度比水小

（5）

实验步骤实验现象实验结论备注
①点燃纯净的氢气发出淡蓝色火焰反应的文字表达式是：

水

通电
氢气+氧气
②在火焰上方罩一个干而冷的烧杯烧杯内有水雾出现有水生成
③用手轻轻触摸烧杯烧杯发烫说明此反应中伴随能量变化，把化学能转变成了热能
（6）④

单项选择题

不含菊糖的药材是（）

A.党参

B.白术

C.木香

D.麦冬

E.苍术
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单项选择题

Many people who work in London prefer to live outside it, and to go in to their offices or schools every day by train, car or bus, even though this means they have to get up early in the morning and reach home late in the evening.

One advantage of living outside London is that houses are cheaper. Even a small flat in London without a garden costs quite a lot to rent. With the same money, one can get a little house in the country with a garden of one’s own.

Then, in the country one can rest from the noise and hurry of the town. Even though one has to get up earlier and spend more time in trains or buses, one can sleep better at night and during weekends and on summer evenings, one can enjoy the fresh, clean air of the country. If one likes gardens, one can spend one’s free time digging, planting, watering and doing the hundred and one other jobs which are needed in a garden. Then, when the flowers and vegetables come up, one has the reward of one who has shared the secret of Nature.

Some people, however, take no interest in country things: for them, happiness lies in the town, with its cinemas and theatres, beautiful shops and busy streets, dance-hails and restaurants. Such people would feel that their life was not worth living if they had to live it outside London. An occasional walk in one of the parks and a fortnight’s (two weeks) visit to the sea every summer is all the country they want. the rest they are quite prepared to leave to those who are glad to get away from London every night.

People who think happiness lies in the town would feel that（）if they had to live it outside London

A. their life was meaningless

B. their life was invaluable

C. they didn’t deserve a happy life

D. they were not worthy of their happy life
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