根据化学方程式计算溶质的质量分数问题,是中学化学计算的难点,为突破这一难点,同学们在学习过程中要善于举一反三,对一道习题,通过定性分析,采用多种解法,以求得拓宽思路,触类旁通,提高解题能力之目的. Calculating the mass fraction of solute in accordance with the chemical equation is a difficult point in the middle school chemistry calculation. To overcome this difficulty, students must be good at taking lessons from each other in the learning process. Through a qualitative analysis, they use a variety of solutions to achieve widening. Ideas, by analogy, improve the ability to solve problems.