物理与工程2025，Vol.35Issue(5)：228-234,7.
基于电导率实验的KCl稀溶液中离子-水分子碰撞截面研究
INVESTIGATION OF ION-WATER MOLECULE COLLISION CROSS-SECTION IN DILUTE KCL SOLUTION BASED ON CONDUCTIVITY EXPERIMENT
摘要
Abstract
Water,an essential substance for life,commonly exists in the form of aqueous solutions in nature.When strong electrolytes dissolve in water,they fully dissociate into free ions,resulting in con-ductive solutions whose conductivity is closely related to ion concentration.Based on L.Onsager's lim-iting law,ionic mobility in infinitely diluted solutions stabilizes,affected mainly by water molecular thermal motion.This study focuses on KCl dilute solutions.At room temperature,it uses low-volt-age,high-precision conductivity measurements to get conductivity data at different concentrations.The data is analyzed and fitted to find limiting ionic mobility and solvent viscosity.With the kinetic theory of molecules,average collision time is calculated.An equivalent hard-sphere model estimates the effec-tive collision cross-section between ions and water molecules in thermal motion.Results show ionic mobility saturates at lower concentrations,and the effective collision cross-section exceeds the geomet-ric one,indicating significant Coulombic interactions during collisions.The experimental methods and analytical models here,based on college level physics and statistical physics,are highly valuable for teaching.They can be used in relevant courses to expand on topics like thermal motion and electrolyte transport,helping students link abstract physical models to real-world processes.关键词
迁移率/平均碰撞时间/碰撞截面/电导率/电解质Key words
mobility/average collision time/collision cross-section/conductivity/electrolyte引用本文复制引用
范宝路,刘阳,周雷,林毅,南峰,沈宇..基于电导率实验的KCl稀溶液中离子-水分子碰撞截面研究[J].物理与工程,2025,35(5):228-234,7.基金项目
淮安市自然科学研究计划项目(HAB201906)资助,江苏省"双创博士"人才项目 （HAB201906）
教育部人文社科青年基金项目(25YJC760067). （25YJC760067）
