题干

 已知A、B、C、D、E五种元素核电荷数依次增大,A原子核内无中子,B的一种单质是自然界中最硬的物质,C是地壳中含量最多的元素,D的最外层电子数与C的最外层电子数相同,且C、D形成的化合物之一是形成酸雨的罪魁祸首,E是地壳中含量居于第二位的金属元素,且其合金用量最多用途最广,请回答下列问题:

(1)写出A、C形成两种液态化合物的分子式 ____ 、____ .

(2)画出D的原子结构示意图 ____  .

(3)防止E锈蚀的方法____ (答出一种即可).

(4)B、D两种元素按质量比3:16形成化合物的分子式 ____ .

上一题 下一题 0.0难度 选择题 更新时间:2017-10-15 12:28:56

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H2O,H2O2,,刷漆等,CS2

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    Health experts are calling for action to increase cancer care and control in the developing world. A medical research paper says cancer was once thought of as a problem mostly in the developed world. But now cancer is a leading cause of death and disability in poor countries as well. Experts from Harvard University and other organizations urge the international community to fight cancer actively, saying it should be fought in the way HIV/AIDS has been fought in Africa.

    Cancer kills more than 7.5 million people a year worldwide. Almost two thirds are in low-income and middle-income countries.

    They discover cancer kills more people in developing countries than AIDS, tuberculosis and malaria combined. But the world spends only 5﹪ of its cancer resources in those countries.

    Felicia Knaul from Harvard Medical School was one of the writers of the paper. She was in Mexico when she was found to have breast cancer. She received treatment there and her experience showed her the sharp difference between the rich and the poor in treating breast cancer.

    Felicia Knaul says, “And we are seeing how this is attacking young women. It's the number two cause of death in Mexico of women thirty to fifty-four. All over the developing world, it's the number one cancer-related death among young women. I think we have to again say that there is much more we could do about it than we are doing about it. ”

    Professor Knaul met community health workers during her work in developing countries. They were an important part of efforts to reduce deaths from the cancer. They were able to persuade people to get tested to prevent the illness. The experts say cancer care does not have to be costly. For example, patients can be treated with lower-cost drugs.