质量守恒定律是化学中的一条重要定律。中客中主要从以下三个方面进行考查：一是从定律本身出发；二是用原子、分子观点解释定律出发；三是定律的外延反映出元素在反应前后种类、质量都不改变出发。一、利用参加反应前后各物质质量总和不变来解题的题型1．确定物质的式量倒1在 The law of conservation of mass is an important law in chemistry. Zhong Kezhong mainly examines the following three aspects: first, proceeding from the law itself; second, starting from the atomic and molecular viewpoints to explain the law; third, the extension of the law reflects that the elements do not change before and after the reaction. First, the use of the type of material to participate in the reaction before and after the sum of the quality of the problem to solve the problem type 1. Determine the quantity of substance