极值法是一种重要的数学思想和分析方法。化学上所谓“极值法”就是对数据不足而感到无从下手的计算或混合物组成判断的题目，采用极端假设（即为某一成分或者为恰好完全反应）的方法以确定混合体系中各物质的名称、质量分数、体积分数，这样使一些抽象的复杂问题具体化、简单化，可达到事半功倍之效果。 -The extremum law is an important mathematical thinking and analytical methods. Chemical on the so-called " extreme value method is the lack of data was impossible to start the calculation or the mixture of the judgment subject to extreme assumptions (ie a particular ingredient or exactly complete reaction) method to determine the material mixed system Name, mass fraction, volume fraction, so that some the abstract complex issues concrete, simplistic, can achieve a multiplier effect.