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问题 问答题

有一包固体A，可能含有CuO、Cu、NaOH、Na2CO3、Ca（OH）2中的几种，取少量的A做如下实验进行探究．试根据实验过程中的现象判断：

（1）气体D是______，沉淀G是______．

（2）写出过程②中一定发生的化学方程式______．

（3）写出过程③发生的化学方程式______．

（4）原固体混合物A中一定含有的物质______．

（5）滤液B中，还可能存在的溶质是______，若要证明该物质是否存在，应该补做的实验是（写出主要的实验步骤、现象及结论）______．

答案

（1）得到的滤液B能与盐酸反应生成气体D，则滤液B中含有碳酸钠，生成的D为二氧化碳，得到的沉淀C能与盐酸反应生成蓝色溶液F，则F为氯化铜，由盐酸与氧化铜反应生成，铜不与盐酸反应，故沉淀G为铜，碳酸钙能与盐酸反应生成二氧化碳气体，沉淀C与盐酸反应无气体产生，故C中不含有碳酸钙，混合物A中不含有氢氧化钙，所以本题答案为：二氧化碳，铜；

（2）加入盐酸产生了二氧化碳，则碳酸钠与盐酸反应生成了氯化钠、二氧化碳和水，所以本题答案为：Na2CO3+2HCl═2NaCl+CO2↑+H2O；

（3）氧化铜能与盐酸反应生成氯化铜和水，所以本题答案为：CuO+2HCl═CuCl2+H2O；

（4）根据推断，原物质中一定含有碳酸纳、氧化铜和铜，所以本题答案为：碳酸纳、氧化铜和铜；

（5）滤液B中还可能含有氢氧化钠，要证明其存在，可以将碳酸钠除去，加入酚酞试液观察是否变红进行判断，所以本题答案为：氢氧化钠，取样品少许，放入试管中，加入水溶解，然后向溶液中加入过量的氯化钙溶液，然后向上层清液加入酚酞试液，若试液变红，则含有氢氧化钠．

问答题

这学期，你一定在老师的带领下进行了好多语文活动吧，下面请展示一下你的活动情况。 （1）【这就是我】

请用几句精彩的语言介绍你自己，尽量表现你的个性，让人过目不忘哦：

                                                                ______________

（2）【漫游语文世界】

商店门牌，电视广告或者报纸杂志等，到处都有语文，请举出一个在生活中发现的关于语文实际运用的例子并简要分析：

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问答题

Exercise, everyone advises! But immediately, when you try, you run into trouble. (46)There is so much contradictory, sometimes incorrect advice about exercising that you become confused. Test yourself on the following true false quiz. It will tell you what you need to know.
1. The best way to reduce the mid-section is to do abdominal exercise.
False. Many people believe that when specific muscles are exercised, the fatty tissues in the immediate area are "burned up." (47)The truth-is that exercise burns fat from all over the body and not from one specific area, regardless of the type of exercise. Of course, if you reduce the fat throughout your body, you will certainly see results around your waistline too!
2. To maintain an adequate level of physical fitness, you need to exercise only twice a week.
False. Studies conducted by NASA, the National Aeronautics and Space Administration, show that unexercised muscles lose their strength very quickly. After 48 to 72 hours, you must use the muscles again to reestablish the good physical effect. And what does that mean to you (48) NASA scientists concluded that while daily exercise is most beneficial, three alternating days each week will maintain an adequate level of physical fitness.
3. To lose weight you should always "work up a good sweat" when exercising.
False. Sweating only lowers body temperature to prevent overheating; it does not help you reduce weight. You may weigh less immediately after a workout, but this is due to water loss. Once you replace the liquid, you replace the weight.
4. If your breathing doesn’t return to normal within minutes after you finish exercising, you’ve exercised too much.
True. Five minutes or so after exercising, your breathing should be normal, your heart shouldn’t be pounding, and you shouldn’t be exhausted. (49) Beneficial exercise is not overly difficult, unpleasant, and exhausting; it is moderate, enjoyable, and refreshing.
5. Walking is one of the best exercises.
True. Walking helps circulation of blood throughout the body, and thus has a direct effect or your overall feeling of health.
6. The minimum amount of time you should spend exercising in a day is 20 minutes.
True. There are more than 400 muscles that attach to your skeleton. (50) A good exercise routine should contract and stretch all these muscles, and this simply cannot be done with four or five exercises in five to ten minutes. From experience, I’ve found that about 20 minutes is the minimum amount of time needed for an adequate workout.
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