题干

电池的“理论比能量”指单位质量的电极材料理论上能释放的最大电能。“金属(M)〜空气电池”(如下图)具有原料易得、能量密度高等优点。该类电池放电的总反应方程式为:4M+nO2+2nH2O=4M(OH) n。下列说法不正确的是(   )

A:“金属(M)〜空气电池”放电过程的正极反应式:  O2+2H2O+4e-=4OH-

B:比较Mg、Al、Zn三种“金属—空气电池”,“Al—空气电池”的理论比能量最高

C:电解质溶液中的阴离子从负极区移向正极区

D:在“M—空气电池”中,为防止负极区沉积Mg(OH)2,宜采用中性电解质及阳离子交换膜

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答案(点此获取答案解析)

C

同类题5

阅读下面的短文,将画线的句子译成英文或中文。

    Stephen Hawking was born in Oxford, England on 8th January, 1942. He went to school in St Allbans, a small city near London. ⑴尽管他做得很好,但是拿不到第一名。

    After leaving school, Hawking went first to Oxford University where he studied physics and then went to Cambridge University where he studied cosmology(宇宙学). As he himself admits, he didn't work hard. He was a very lazy student, and did very little work. However, he still got high marks.

   ⑵ 在他20岁的时候,他的身体出毛病了。 He started to knock into things. When he visited his family at Christmas time, his mother was so worried that she made him see a doctor. Hawking was sent to hospital for tests. Finally, the result came back. Hawking had motor neuron disease(运动神经元病). ⑶The illness would make him unable to speak, breathe or move without the help of a machine. Doctors said they had no way to help him. He would die before 23.

    At first, Hawking became very sad. After a while, though, he began to see his life in a different way. As he later wrote, “Before my illness was diagnosed(诊断), I had been very bored with life. There had not seemed to be anything worth doing. But shortly after I came out of hospital, ⑷I suddenly realized that there were a lot of valuable things I could do.” Then Hawking got married and found a job at Cambridge University as a professor. ⑸He strongly believes that his story shows that nobody should lose hope, no matter how bad their situation is. “Life is not fair.” He once said. “You just have to do the best you can in your own situation.”

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