高三学生进入复习阶段训练时,比较惧怕计算型选择题,我在教学中以“物质的量守恒法”给予学生点拨,收效明显,同学们不妨一试, 细心去领会这种方法——“物质的量守恒法”:根据化学反应方程式中所求的各反应原子,在反应前后其物质的量始终不变,从而建立等式求解得答的方法. 例1 已知2.1g KOH和1.6g硫粉混合 When senior high school students enter the recitation training stage, they are more afraid of the calculation-type multiple-choice questions. In teaching, I give the students a “conservation of material quantity law” to give the students a lesson. The results are obvious. Students may wish to try and carefully understand this method. The method of conservation of quantities": According to the chemical reaction equations for each reaction atom, the amount of the substance before and after the reaction is always constant, so as to establish a method to solve the equation. Example 1 2.1g of KOH and 1.6g of sulfur are known Powder mixing