【作者】 邵利民；

【Author】 Limin Shao;Department of Chemistry, University of Science and Technology of China;

【机构】 中国科学技术大学化学系；

【摘要】 终点误差是滴定分析的重要内容,现行教材为之提供了不同类型的计算公式。但是,基于公式的计算策略存在公式数量多、适用范围窄等局限性,致使终点误差难以掌握。为了解决这一问题,我们提出了终点误差的体积定义式,在此基础上建立了去公式化的终点误差计算策略。去公式化的计算策略不再涉及形式复杂的公式,显著减轻了记忆负担;紧密联系化学平衡知识,方便直观,运算强度较低。去公式化的计算策略统一了酸碱滴定、配位滴定、氧化-还原滴定以及沉淀滴定的终点误差计算,而且可以用于准确滴定判别。这种计算策略避免了机械记忆公式,提升了学习兴趣,将学习重点放在平衡体系的分析和处理。本研究作为当前形势下分析化学教学改革的一个尝试,对传统课程内容进行优化,去冗存精,使其简明凝练,重点突出,定量分析的主旨更加明晰。更多还原

【Abstract】 Titration error plays a key role in quantitative chemical analysis. Calculations of titration error in most textbooks are implemented with various formulae. The formula-oriented strategy has such disadvantages as too many complicated formulae and limited applicability for each. To address this problem, we redefined titration error by using the volumes of titrant and analyte solutions(as opposed to using concentrations), and then developed a formula-free strategy for the calculation. This strategy relieves students from rote memorization(non-essential in analytical chemistry); features intuitive concept, easy operation, and close connection to the knowledge of chemical equilibrium systems(essential in analytical chemistry). This strategy allows titration errors of all four types of titration(acid-base, EDTA, redox, and precipitation) to be calculated in a universal way. This strategy can also be applied to determine the feasibility of an accurate titration scheme, which is essentially to calculate a variant of titration error.更多还原