凝固点降低法测定摩尔质量实验试剂的改进  

Improvement of Experimental Reagent for the Determination of Molar Mass by Freezing Point Reduction Method

作　　者：吴林钢[1] 洪琴 赵云兰 李祖贵 戴杰 孙伟坚 李伟刚 王宁 王淋 曾小文 洪立 陈定奔[1] 陈丹[1] 钟爱国[1] 

机构地区：[1]台州学院医药化工学院,浙江台州318000

出　　处：《当代化工》2018年第2期232-235,239,共5页Contemporary Chemical Industry

基　　金：浙江省自然科学基金;台州学院校立教改项目资助;项目编号为LY15B030001

摘　　要：目前在高校基础无机化学和物理化学实验课程中开设的"凝固点降低法测定相对分子质量"实验,一般选用"萘-环己烷"或"萘-苯"为溶质和溶剂。萘、环己烷、苯均是致癌物质,污染环境,严重伤害实验教学人员的身体。用"蔗糖-水"或者"尿素-水"替代"萘-环己烷"或"萘-苯"可消除环境污染;对常用的通过凝固点降低法来测定相对分子质量的实验试剂进行更改替换,选用水作溶剂测定尿素的摩尔质量,解决了环保问题。研究了水+尿素体系的步冷曲线,确定了水和尿素水溶液的凝固点值。改进后的试剂尿素取用方便,测定其摩尔质量相对误差可以控制在1%左右。At present, in the course of basic inorganic chemistry and physical chemistry experiment in universities, the method of ＂freezing point reduction＂ to determine molar mass usually adopts ＂naphthalene-cyclohexane＂ or ＂naphthalene-benzene＂ as solute and solvent. Naphthalene, cyclohexane and benzene are carcinogenic substances that can pollute the environment and seriously injure the body of experimental teaching staff. ＂Sugar water＂ or ＂urea water＂ instead of ＂naphthalene cyclohexane＂ or ＂naphthalene benzene＂ can eliminate environmental pollution. In this paper, the common method of freezing point reduction for the determination of the molar mass of organic compounds was improved. The molar quality of urea was determined with water as solvent, and the environmental problems were solved. The step cooling curve of water ＋ sucrose system was studied, and the freezing point of water solution was determined. The urea as improved reagent is convenient to be used, and the relative error of its molar mass can be controlled about 1%.

关 键 词：化学专业 物理化学实验 凝固点 摩尔质量 尿素 

分 类 号：TQ644.30[化学工程—精细化工]