根据化学反应前后“元素质量守恒”在解题时灵活地加以运用,常常能非常快捷地解决用常规解法显得很烦琐的问题,是最常用的守恒法之一.例1将一定质量的碳酸钙和单质炭的混合物置于坩埚中充分灼烧,假定能将产生的气体全部收集起来,结果发现所得气体质量恰好等于原混合物质量,试求原混合物中碳元素的质量分数.解析:本题共发生两个反应Ca CO3高温Ca O+CO2↑C+O2 According to the chemical reaction before and after the “elemental mass conservation ” in the solution to the flexible use of the problem, often very quickly to solve the problem with the conventional solution is very cumbersome, is one of the most commonly used conservation method. Calcium carbonate and carbon monoxide mixture placed in a crucible full of ignition, assuming the gas can be collected all together and found that the resulting gas quality is exactly equal to the quality of the original mixture, try the original mixture of carbon mass fraction. A total of two reactions Ca CO3  high temperature Ca O + CO2 ↑ C + O2 