题目

Frankly, I very much appreciate myself. Yes, I admit I’m in many respects not as good as other people, but I don’t think I’m always not good. When I find what I’ve done or written is okay, I’ll remain pleased with myself for quite a few days, and in case I receive praise for it, I’ll even become so excited as to add a few words to glorify myself.True, I’m not modest at all. People may call me conceited (自负的). But I think otherwise.I also appreciate other people. I appreciate anything good. Isn’t it unfair to forget appreciating myself while appreciating others?We Chinese 镁条放置在空气中一段时间表面会形成一层黑色物质。化学小组查得以下资料：I．常温下，空气中的氮气和稀有气体不会与镁发生反应。II．无水CaCl2固体有较强的吸水性，能吸收空气中的水蒸气。为探究镁表面黑色物质的成因是与空气中的哪些成分有关，开展以下实验探究。[实验1]按图所示装置进行实验，数日后，只观察到镁条表面变暗，没有出现黑色物质。（1）查阅文献获知，镁条表面变暗是镁与氧气作用形成的，该反应的化学方程式为_____________________。（2）据此现象，可说明只有_________和________无法使镁生成黑色物质。 [实验2]按图所示装置进行实验，数日后，只观察到镁条表面变暗，没有出现黑色物质。（3）该实验的目的是____________________________。[实验3]按图所示装置进行实验，数日后，观察到镁条表面出现黑色物质。（4）得出“镁条变黑一定与水有关”的结论，依据的两个实验是__________（填实验序号）。（5）化学小组认为据此现象还不足以得出最终结论，于是 补做了一个实验：将图3中的潮湿的空气换成_______进行实验，数日后，观察到镁条表面无明显变化。（6）根据上述四个实验，化学小组得出结论：镁表面的黑色物质是镁与_______________共同作用的结果。