Exploring students'chemical reasoning pathways: From phenomenon to structure in context-based chemistry learning

This study investigates students' chemical reasoning pathways from the phenomenological to the structural level within a context-based chemistry learning framework. Utilizing a mixed-method explanatory sequential design, the research involved 91 preservice teacher students who had studied weak bases and Bronsted-Lowry acid-base concepts. The instrument, validated with an Aiken's V of 0.92 and a Cronbach's Alpha of 0.89, consisted of contextual essay questions centered on ammonia as a cleaning agent, assessing reasoning at phenomenological, mechanistic, and structural levels. Scoring consistency between two experts yielded a Cohen's Kappa of 0.925. Quantitative findings revealed that while most students demonstrated linear reasoning, instances of regression and inconsistency emerged, particularly during transitions to higher reasoning levels. Phenomenological reasoning achieved the highest average score (M = 4.93; SD = 0.25), whereas structural reasoning scored lowest (M = 4.12; SD = 0.68). Qualitative analysis reinforced these results, highlighting cognitive bottlenecks and misconceptions, especially in mechanistic and structural reasoning. The study concludes that although students can progress through reasoning stages, challenges persist, notably at the mechanistic stage, with some regression at the structural level. These insights underscore the necessity for instructional strategies that support deeper connections between macroscopic phenomena and molecular-level explanations.