This paper reports on an interview study of 18 Grade 10–12 students’ model-based reasoning of a chemical reaction: the reaction of magnesium and oxygen at the submicro level. It has been proposed that chemical reactions can be conceptualised using two models: (i) the particle model, in which a reaction is regarded as the simple combination and rearrangement of reactant particles and does not involve any change in the identity of the reactants, and (ii) the atomic model, wherein a reaction involves the transformation of one chemical species into another. This paper suggests that although the particle model looks simpler than the atomic model, it can help to support the learning of some advanced chemical concepts such as energetics and collision theory. Therefore, it is postulated that students who reason using the particle model are able to demonstrate some advanced ideas about chemical reactions. The conceptualisation of reactions in terms of the atomic model and the particle model allows a flexible understanding of students’ learning. Students’ representations of the reaction between magnesium and oxygen were analysed with reference to the two models. The models were found to be useful in assessing the students’ understanding of the reaction and revealing the novel ways that the students reasoned the chemical reaction. In addition, a student who used the particle model to represent the reaction was found to explain the reaction in terms of some energetics and kinetics concepts. The study offers insights for curriculum planners and teachers into the potential of these two models to help students understand chemical reactions.

中文翻译：

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学生对化学反应的可视化–对粒子模型和原子模型的见解

本文报道了一项对18名10-12年级学生基于模型的化学反应推理的访谈研究：镁和氧的反应在亚微水平上进行。已经提出可以使用两个模型来概念化化学反应：（i）粒子模型，其中反应被视为反应物颗粒的简单组合和重排，并且不涉及反应物身份的任何变化，以及（ii）原子模型，其中反应涉及一种化学物质向另一种化学物质的转化。本文建议，尽管粒子模型看起来比原子模型更简单，它可以帮助支持一些高级化学概念的学习，例如能量学和碰撞理论。因此，假设推理使用粒子模型的学生能够证明一些有关化学反应的高级思想。根据原子模型和粒子模型对反应进行概念化，可以灵活地了解学生的学习情况。参照两个模型分析了学生对镁与氧之间反应的表示。发现该模型对于评估学生对反应的理解以及揭示学生推理化学反应的新颖方法很有用。另外，使用粒子模型的学生发现代表反应的反应是根据一些能量学和动力学概念来解释反应的。这项研究为课程计划者和教师提供了有关这两种模型的潜力的见解，以帮助学生理解化学反应。