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【多选题】
质量守恒定律是一条重要规律．请利用该规律的相关知识回答下列问题． （1）蜡烛在空气中燃烧时生成二氧化碳和水．由此判断蜡烛中一定含有的元素是______（填元素符号），判断的依据是______． （2）某同学取一根洁净的铜丝，称量其质量为m 1 g，将此铜丝加热并冷却后再次称量，其质量为m 2 g，则m 1 ______m 2 （填“＞”、“＜”或“=”），产生这一结果的原因是______． （3）在密闭容器中放入X、Y、Z、W四种物质并使其发生反应，测得有关数据如下表．关于此反应的认识正确的是______（填字母序号）． 物质 X Y Z W 反应前的质量（g） 2 1 16 16 一段时间后的质量（g） 17 m 6 11
A.
m=1
B.
该反应为分解反应
C.
X与Z的化学计量数之比是3：2
D.
若该反应充分进行，反应后W仍有剩余．
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相关题目：
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A.
3mm
B.
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C.
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