大学化学 >> 2025, Vol. 40 >> Issue (7): 315-320.doi: 10.12461/PKU.DXHX202408089

化学实验 上一篇    下一篇

碘量法测铜实验中“异常现象”的探究

陈蓝苍鸿1, 余行泰1, 赵天磊2, 姚奇志1,3   

  1. 1 中国科学技术大学化学与材料科学学院, 合肥 230026;
    2 中国科学技术大学地球与空间科学学院, 合肥 230026;
    3 化学国家级实验教学示范中心(中国科学技术大学), 合肥 230026
  • 收稿日期:2024-08-20 录用日期:2024-10-16 发布日期:2025-07-01
  • 通讯作者: 姚奇志, 赵天磊 E-mail:qzyao@ustc.edu.cn;zhaotian@ustc.edu.cn
  • 基金资助:
    安徽省高等学校省级质量工程项目(2021jyxm1730, 2021xxkc205)；中国科学技术大学本科质量工程项目(2024xjyxm083)；首批教育部虚拟教研室(大学化学实验课程群虚拟教研室)建设项目； 2024 年教育部实验教学和教学实验室建设研究项目(SYJX2024-068)

Exploration of Abnormal Phenomena in Iodometric Copper Quantitation Experiment

Lancanghong Chen1, Xingtai Yu1, Tianlei Zhao2, Qizhi Yao1,3   

  1. 1 School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China;
    2 School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;
    3 National Demonstration Center for Experimental Chemistry Education (University of Science and Technology of China), Hefei 230026, China
  • Received:2024-08-20 Accepted:2024-10-16 Published:2025-07-01
  • Contact: Qizhi Yao, Tianlei Zhao E-mail:qzyao@ustc.edu.cn;zhaotian@ustc.edu.cn

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摘要： “碘量法测定铜合金中铜含量”是大学分析化学实验中重要的实验内容之一，某学生在进行该实验时，错将20% KSCN溶液当作HAc-NaAc缓冲溶液进行实验。尽管其最终沉淀仍为CuSCN，但滴定结果存在显著差异。针对这一异常现象，笔者通过文献调研，提出了几点可能的解释，并设计相应实验进行探究和验证。通过对实验中间产物的系统分析，证实了相关的反应过程和机制，阐明了异常现象产生的原因。这不仅培养了学生分析和解决问题的能力，也训练了学生逻辑思维和科学实验思维。

关键词: 碘量法, 铜测定, 异常现象, 反应机理

Abstract: The iodometric determination of copper in alloys represents a fundamental experiment in analytical chemistry education. This study examines a notable case where a student erroneously used 20% KSCN solution instead of the prescribed HAc-NaAc buffer solution, yet surprisingly obtained CuSCN precipitate matching that of the standard procedure, albeit with significant discrepancies in titration results. Through systematic investigation of reaction intermediates and experimental validation, we elucidate the underlying chemical mechanisms responsible for this anomaly. This pedagogical approach not only enhances students' problem-solving capabilities but also demonstrates proper scientific investigation methodology for addressing unexpected experimental outcomes.

Key words: Iodometric method, Copper determination, Abnormal phenomena, Reaction mechanism