题干

下列说法正确的是(   )

A:在海轮船壳上镶入锌块保护海轮,利用的是牺牲阳极的阴极保护法

B:KNO3溶液和CH3OONH4溶液均显中性.两溶液中水的电离程度相等

C:若1 molNa2O2与足量水反应产生O2,理论上转移的电子数约为2×6.02×1023

D:用pH 均为2 的盐酸和醋酸分别中和等物质的量的NaOH,消耗醋酸的体积更大

上一题 下一题 0.0难度 选择题 更新时间:2019-03-30 08:28:45

答案(点此获取答案解析)

A

同类题5

阅读理解

    For years I wanted a flower garden. But then we had Matthew. And Marvin. And the twins, Alisa and Alan. And then Helen. I was too busy raising them to grow a garden.

    Money was limited, as well as time. Often when my children were little, one of them would want something that cost too much, and I’d have to say, “Do you see a money tree outside? Money doesn’t grow on trees, you know.”

Finally, all five got through high school and college and were off on their own. I started thinking again about having a garden. I wasn’t sure, though, I mean, gardens do cost money.

    Then, one spring morning, on Mother’s Day, I was working in my kitchen. Suddenly, I realized that cars were tooting their horns as they drove by. I looked out of the window and there was a new tree, planted right in my yard. I thought it must be a weeping willow, because I saw things blowing around on all its branches.

    There was a money tree in my yard !It was true! There were dollar bills, one hundred of them, taped all over that tree. There was also a note attached: “IOU eight hours of digging time. Love. Marvin.”

    Marvin kept his promise, too. He dug up a nice ten-by-fifteen foot bed for me. And my other children bought me tools, ornaments, a trellis, a sunflower stepping stone and gardening books.

    That was three years ago. My garden’s now very pretty, just like I wanted. When I go out and weed or tend my flowers, I don’t seem to miss my children as much as I once did. It feels like they are right there with me. I think about what my children did for me, and I get tears in my eyes every time.

    I’m still not sure that money grows on trees. But I know love does!