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一、实验说明苏教版选修6《实验化学》专题1课题3“硝酸钾晶体的制备”中,提到了影响晶粒生成的条件:晶体颗粒的大小与结晶条件有关,溶质的溶解度越小,溶液的浓度越高,溶剂的蒸发速度越快,或溶液冷却得越快,析出的晶粒就越细小;反之,可得到较大的晶体颗粒。教材中没有设计相关实验说明,因此,“影响晶粒生成的条件”很容易成为一段记忆性文字,学生没有直观的认识与理解。而在苏教版选修4《化学反应原理》专题3第四单元“难溶电解质的沉淀溶解平衡”中,教材以PbI_2的生成介绍了沉淀溶解平衡原理。所以可考虑将选修4与选
First, the experimental instructions Sujiao version 6 “Experimental Chemistry” topic 1 3 “potassium nitrate crystal preparation ”, mentioned the conditions affecting the crystal grain: the size of the crystal particles and the crystallization conditions, the solute solubility Small, the higher the concentration of the solution, the faster the evaporation rate of the solvent, or the faster the solution is cooled, the smaller the precipitated crystal grains; on the contrary, larger crystal particles can be obtained. There is no experimental description of the design in the textbook. Therefore, “the conditions that affect the grain generation” can easily become a memorized text, and the students do not have an intuitive understanding and understanding. In the Sujiao version of the elective 4 “chemical reaction principle” the third unit of the fourth unit “insoluble dissolved electrolyte precipitation balance ”, the textbook to PbI2 generation introduced precipitation dissolution equilibrium principle. So consider elective 4 and election