已知：Pb的化合价只有+2、+4，且+4价的Pb具有强氧化性，能氧化浓HCl生成Cl₂；PbO₂不稳定，随温度升高按下列顺序逐步分PbO₂→Pb₂O₃→Pb₃O₄→PbO．现将a mol PbO₂加热分解，收集产生的O₂；向加热后所得固体中加入足量的浓盐酸，收集产生的Cl₂．加热反应后所得固体中，Pb²⁺占Pb元素的物质的量分数为x；两步反应中收集的O₂和Cl₂的物质的量之和为y mol．

试回答下列问题：

（1）试写出Pb₂O₃与浓盐酸反应的化学方程式 ____．

（2）用含x与a的表达式表示产生的O₂、Cl₂的物质的量n（O₂）= ____　，n（Cl₂）= ____　．

（3）写出y与a、x的函数关系式：　 ____．

（4）若两步反应中O₂和Cl₂的物质的量之比为5：3，则剩余固体中含有的物质为 ____　；其物质的量之比为 ____．

（5）PbO₂和Pb经常作制造蓄电池的原材料，铅蓄电池的工作原理：

Pb+PbO₂+2H₂SO₄2PbSO₄+2H₂O．现有一种生产NH₄NO₃的新工艺，电解NO制备NH₄NO₃，其工作原理如图所示，为使电解产物全部转化为NH₄NO₃，需补充物质A，A是　 ____，说明理由： ____

生产1吨硝酸铵需消耗Pb的物质的量是 ____　kg（保留到整数）．

观察漫画，回答下列问题。

先通读下面的短文，掌握其大意，然后从A、B、C、D四个选项中选择可以填入空白处的最佳答案．

    One night I saw something on the news that made me sad．It was1a group of homeless(无家可归的)people sleeping outside in the cold．

    So I decided to start a2to raise many for the homeless．I called it the Rock Club,At the beginning,there were only five members in it，3that quickly grew to about twenty．I didn't have to ask anyone if they wanted to be a4．In fact，they came up to me and asked me if they could5the club!

    We spent all of our free time on rock painting．We painted animals,flowers and even the names of sports teams on our rocks．We'd go around the school to6people who would buy them．By Christmas，we had raised thirty．three dollars and then we gave the money to a homeless shelter(收容所)in town．We all felt7that we could do something to help the homeless．

    A few days later,a newspaper reporter(记者)came to our school to8with us about our club and took a photo of us．The photo and article(文章) 9in the newspaper the next day．Later,10school,joined by three other schools，started a project for kids to help homeless shelters．

    Something as simple(简单的)as some painted rocks and a few caring kids made me know that I don't need much to make a difference．