Abstract Why does the density of straight-chain alkanes increase with carbon atom count, while that of straight-chain chlorinated hydrocarbons decreases? This study analyzes the density variation patterns of common organic isomers through data analysis. By integrating macroscopic identification with microscopic exploration, it introduces the concepts of light atoms and heavy atoms. Through evidence-based reasoning and model-based cognition, a practical density calculation model for organic compounds is constructed. The research elucidates the compositional and structural factors influencing organic compound densities, clarifies the density variation patterns of common isomers in high school, and provides references for establishing core disciplinary concepts and developing essential competencies in organic chemistry teaching.
ZHUO Jun-Qiao. Subject Understanding of Organic Matter Density Variation Rule: Computational Models, Influencing Factors, and Teaching Suggestions[J]. Chinese Journal of Chemical Education, 2026, 47(9): 96-101.
