确定有关量的范围是化学平衡计算的重要题型 ,也是学习的难点 ,如果根据可逆反应的特点 (即可逆反应都是不能进行到底的反应 ,平衡时反应物的浓度大于零 ) ,再运用极端思维方法 (即假设可逆反应正向或逆向反应进行完全 ) ,就能迅速解决此类问题 .例 1　在一个密闭容器中进行如 Determining the range of relevant quantities is an important issue for chemical equilibrium calculations, and it is also a difficult learning point. If the characteristics of reversible reactions are used (reversible reactions cannot react in the end, and the concentration of reactants at equilibrium is greater than zero), then extremes are used. The thinking method (that is, assuming that the forward or reverse reaction of the reversible reaction is complete) can quickly solve such problems. Example 1 In a closed container, such as