题干

学习了CO2的有关知识后,同学们查阅资料发现Mg能在CO2中燃烧:2Mg+CO22MgO+C,所以镁着火不能用CO2来灭火,但没有找到有关Na能否与CO2反应的介绍.于是同学们展开了钠着火能否用CO2来灭火的探究.

【提出猜想】钠能发生类似于CO2与镁的反应,可能的化学方程为 ____  .

【实验】将燃着的钠伸入装有CO2的集气瓶中,钠能在集气瓶中继续燃烧.进一步

【查阅资料】得知:

①Na2O是白色固体,能与CO2反应生成Na2CO3,与H2O反应生成NaOH.

②Na2CO3的存在会干扰NaOH的检测.

基于以上资料,同学们认为钠在CO2中燃烧的产物情况有所不同,并对产物提出了以下几种猜想:

①Na2O、C;②____  、C;③NaOH、C;④Na2O、Na2CO3、C

通过理论分析,猜想____ (填序号)肯定错误的,理由是 ____ .

【验证猜想】

步骤 实验操作 主要实验现象 结论(燃烧产物判断)

(1)将产物溶于适量水中 部分溶解,试管底部有黑色固体 燃烧产物中肯定有C

(2)取少量(1)所得上层溶液,加入过量的CaCl2溶液,产生现象为____ ,则燃烧产物中肯定有Na2CO3

(3)取少量(2)所得上层清液,加入____ ,溶液变红,则燃烧产物中肯定有 ____ 

【交流讨论】在步骤(2)中CaCl2溶液为什么要加入至过量?其原是:____ .

【结论】猜想 ____ (填序号)是正确的.

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答案(点此获取答案解析)

4Na+CO22Na2O+C,Na2CO3,\u2462,NaOH\u4e2d\u6709\u6c22\u5143\u7d20\u800c\u53cd\u5e94\u7269\u4e2d\u6ca1\u6709\u6c22\u5143\u7d20\uff0c\u6839\u636e\u8d28\u91cf\u5b88\u6052\u5b9a\u5f8b\u53ef\u77e5\u2462\u95

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