问题 填空题

氢氧燃料电池是符合绿色化学理念的新型发电装置.右图为电池示意图,该电池电极表面镀一层细小的铂粉,铂吸附气体的能力强,性质稳定,请回答:

(1)氢氧燃料电池的能量转化主要形式是______,在导线中电子流动方向为______(用a、b 表示).

(2)负极反应式为______.

(3)电极表面镀铂粉的原因为______.

(4)该电池工作时,H2和O2连续由外部供给,电池可连续不断提供电能.因此,大量安全储氢是关键技术之一.金属锂是一种重要的储氢材料,吸氢和放氢原理如下:

Ⅰ.2Li+H2

  △  
.
 
2LIH

Ⅱ.LiH+H2O=LiOH+H2

反应Ⅰ中的还原剂是______,反应Ⅱ中的氧化剂是______.

答案

(1)该装置把化学能转变为电能,所以是原电池;发生反应时,氢气失电子,氧气的电子,所以电子的流动方向是由由a到b.

故答案为:由化学能转变为电能;由a到b.

(2)负极上氢气失电子和氢氧根离子生成水,所以电极反应式为 H2+2OH--2e-=2H2O.

故答案为:H2+2OH--2e-=2H2O.

(3)该电池电极表面镀一层细小的铂粉,增大了电极单位面积吸附H2、O2分子数,相当于增大反应物的浓度,所以加快电极反应速率.

故答案为:增大电极单位面积吸附H2、O2分子数,加快电极反应速率.

(4)2Li+H2

  △  
.
 
2LiH,该反应中锂失电子发生氧化反应,所以锂是还原剂;LiH+H2O=LiOH+H2↑,该反应中H2O得电子生成氢气,发生还原反应,所以H2O是氧化剂.

故答案为:Li;   H2O.

阅读理解

B

Your body, which has close relations with the food you eat, is the most important thing you own, so it needs proper treatment and proper nourishment(营养). The old saying "An apple a day keeps the doctor away. " is not as silly as some people think. The body needs fruit and vegetables because they contain vitamin C. Many people take extra vitamins in pill form(丸剂), believing that these will make them healthy. But a good diet is made up of nourishing food and this gives all the vitamins you need. The body doesn't need or use extra vitamins, so why waste money on them?

In the modem western world, many people are too busy to bother about eating properly. They throw away the good habits and throw anything into their stomachs, eating hurriedly and carelessly. The list of illnesses caused or made worse by bad eating habits is frightening.

41. From the first sentence we know that ________,

A. all kinds of food you eat can be made into nourishment

B. your body is made up of the food you eat.

C. what you eat has great effect on your health

D. the more you eat, the better you will feel

42. How do you understand the old saying underlined in the passage?

A. Eating apples regularly brings lots of benefits to our health.

B. Doctors are no longer necessary if we eat an apple every day.

C. The apple is the best among all kind of fruits.

D. An apple is a good way to cure illnesses.

43. What can we conclude from the second paragraph?

A. Our bodies need food, or we can't live.

B. Often eating apples is a good habit.

C. Taking extra vitamin pills is completely useless.

D. A good diet is of great importance for our health.

44. In modern western countries, ________.

A. people don't want to pay more attention to their eating

B. lots of people's illnesses are caused or made worse by bad eating habits

C. people throw everything into their stomachs without digestion(消化)

D. people are only too busy to cook meals for themselves

45. If we want to keep healthy, we should ________ .

A. only eat an apple a day       

B. eat properly

C. take as many vitamin pills as possible

D. throw everything into our stomachs slowly and carefully

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