问题 选择题

LiFePO4可用于电动汽车.电池反应为:FePO4+Li

放电
充电
LiFePO4,电解质为导电固体.下列有关LiFePO4电池的说法正确的是(  )

A.该电池可用水作电解质溶液

B.充电时,电池内部的Li+向阳极移动

C.充电阳极反应LiFePO4-e-=FePO4+Li+

D.放电时正极材料的质量减少

答案

A.放电时金属锂做负极,锂可与水发生反应,故A错误;

B.充电时,属于电解池,阳离子向阴极移动,故B错误;

C.充电时阳极反应:LiFePO4-e-=FePO4+Li+,故C正确;

D.放电时,是原电池的工作原理,正极反应为:FePO4+Li++e-═LiFePO4,正极材料的质量增加,故D错误.

故选C.

单项选择题

(C)

When it comes to friends, I desire those who will share my happiness, who possess wings of their own and who will fly with me. I seek friends whose qualities illuminate me and train me up for love. It is for these people that I reserve the glowing hours, too good not to share.

When I was in the eighth grade, I had a friend. We were shy and "too serious" about our studies when it was becoming fashionable with our classmates to learn acceptable social behaviors. We said little at school, but she would come to my house and we would sit down with pencils and paper, and one of us would say: "Let’s start with a train whistle today." We would sit quietly together and write separate poems or stories that grew out of a train whistle. Then we would read them aloud. At the end of that school year, we were changing into social creatures and the stories and poems stopped.

When I lived for a time in London, I had a friend, he was in despair and I was in despair. But our friendship was based on the idea in each of us that we would be sorry later if we did not explore this great city because we had felt bad at the time. We met every Sunday for five weeks and found many excellent things. We walked until our despairs disappeared and then we parted. We gave London to each other.

For almost four years I have had remarkable friend whose imagination illuminates mine. We write long letters in which we often discover our strangest selves. Each of us appears, sometimes in a funny way, in the other’s dreams. She and I agree that, at certain times, we seem to be parts of the same mind. In my most interesting moments, I often think:"Yes, I must tell..." We have never met.

It is such comforting companions I wish to keep. One bright hour with their kind is worth more to me than the lifetime services of a psychologist,who will only fill up the healing silence necessary to those darkest moments in which I would rather be my own best friend.

In the darkest moments, the author would prefer to().

A. seek professional help

B. be left alone

C. stay with her best friend

D. break the silence

判断题