凝固点降低法测摩尔质量实验改进  

Improvement of Teaching Experiment about the Determination of Molar Mass by Freezing Point Depression Method

作　　者：何漫 高美 廖知常 王雪飞 田志远 陈波珍 HE Man;GAO Mei;LIAO Zhichang;WANG Xuefei;TIAN Zhiyuan;CHEN Bozhen(School of Chemical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大学化学科学学院,北京100049

出　　处：《实验室研究与探索》2021年第3期212-215,共4页Research and Exploration In Laboratory

基　　金：2019年北京高等教育本科教学改革创新项目(201914430001)。

摘　　要：凝固点降低法测摩尔质量是本科物理化学实验教学的经典内容之一,现有教材多注重摩尔质量的测定,而忽视稀溶液依数性原理的介绍。实验教学要将操作技能培训和知识强化相结合,因此做如下改进:将给定溶剂的凝固点降低常数由讲义提供改为学生自行测量;将验证某种化合物摩尔质量改为测量未知化合物摩尔质量;实验中将学生分为两组,分别完成上述两项工作,前者的结果为后者的参数,结果相互验证。实践表明,改进的实验方案可以满足教学需要,使学生对知识点的理解更深入,学习积极性也大大提高。The determination of molar mass by freezing point depression method is a classical teaching experiment of physical chemistry for undergraduate student.In present teaching books the main task of such experiment is to verify the molar mass of specific solute while generally ignoring elucidating the underlying mechanism of colligative property of dilute solution.For teaching experiment,both the basic operational training and acknowledge reinforcement are important.Taking this,we optimized the experiment as following:firstly,the freezing point reduction constant of solvent will not be given but need to be measured by student themselves;secondly,replace the simple verification of the molar mass of specific known chemical with determining that of an unknown compound.In a typical protocol,students were divided into two groups and asked to complete the above two tasks respectively with the result of the formers acting as the parameter for determining the molar mass of unknown compound,in which results from two groups enabled mutual authentication.The results showed that the modification on conventional processes fully meets the needs of teaching and students involved exhibited better understanding on the related basic conception and higher learning enthusiasm.

关 键 词：依数性 凝固点降低 摩尔质量测定 物理化学实验 

分 类 号：O642[理学—物理化学]