大学化学 >> 2022, Vol. 37 >> Issue (6): 2108030.doi: 10.3866/PKU.DXHX202108030

师生笔谈 上一篇    下一篇

关于对消法测定电池电动势实验中标准电池的讨论

郭慧林(), 许文华   

  • 收稿日期:2021-08-13 录用日期:2021-10-11 发布日期:2021-12-01
  • 通讯作者: 郭慧林 E-mail:hlguo@nwu.edu.cn
  • 作者简介:郭慧林, Email: hlguo@nwu.edu.cn
  • 基金资助:
    教育部高等学校化学类专业教学指导委员会教学研究与实践项目(H20210602);教育部高等学校化学类专业教学指导委员会教学研究与实践项目(H20210603);2019年陕西省线下一流本科课程建设项目(物理化学);西北大学首批课程思政建设专项优秀教学团队“三寓三式”课程思政化学教育团队(xm05201461)

Discussion on Standard Cells during the Measurement of Cell Potential Using the Compensation Method

Huilin Guo(), Wenhua Xu   

  • Received:2021-08-13 Accepted:2021-10-11 Published:2021-12-01
  • Contact: Huilin Guo E-mail:hlguo@nwu.edu.cn

摘要:

韦斯顿标准电池,作为很长时间里的国际电压标准,为电化学的发展做出了很大贡献。大学物理化学的常见实验“对消法测定电池电动势”即采用了标准电池。然而目前物理化学教材中关于标准电池的内容较为简单,且学生容易将汞齐电极与一般金属电极混淆。本文从标准电池的表达式、电极反应与电池反应出发,利用能斯特方程分析了影响电池电动势的主要因素,讨论了电解质不饱和与饱和时电动势的可逆性、负极标准电极电势的内涵,并结合电池温度系数讨论了电池电动势的稳定性,探讨了对消法实验中标准电池的选择对测量结果的影响。讨论结果弥补了教材和教学中存在的不足,可为同行教学与学生学习提供一定参考。

关键词: 标准电池, 韦斯顿电池, 电动势, 汞齐电极, 标准电极电势

Abstract:

As the voltage standard used for a very long time, Weston standard cells have made great contributions to electrochemistry. They also appear in the college-level physical chemistry experiment "Reversible cell potential measurement of electrochemical cells using the compensation method". However, the content on standard cells in physical chemistry textbooks is relatively brief and students are prone to confusing amalgam and metal electrodes. Several aspects of standard cells are presented in this paper. The reactions occurring at the negative and positive electrode, as well as the overall reaction, the factors influencing the reversible cell potential have been analyzed using the Nernst equation. The stability of the reversible cell potential has been discussed in terms of the cell temperature coefficient. Moreover, the reversibility and role of amalgam electrodes have been clarified. The effect of the selection of standard cells on the measurement results has also been discussed. These make up for the shortcomings in teaching and teaching materials, and may provide reference for both peer teaching and student learning.

Key words: Standard cells, Weston cells, Reversible cell potential, Amalgam electrodes, Standard electrode potential

MSC2000: 

  • G64