Cognitive Diagnosis of Upper-Secondary Students’ Conceptions in Ionization Equilibrium Based on the Rule Space Model

Evaluating students' cognitive understanding of core concepts and identifying learning path aligned with their cognitive developmental patterns are critical for enhancing conceptual mastery in chemistry. This study employed the Rule Space Model to investigate students' cognitive characteristics and learning path in comprehending the conceptual network centered on "ionization equilibrium." Within this framework, nine key attributes were identified, and corresponding assessment instruments comprising 23 test items were developed. The assessment was administered to 340 upper-secondary school students in China, with systematic scoring and analysis of their responses. The findings reveal that: (1) The assessment demonstrates satisfactory reliability and validity; (2) Students exhibited significant cognitive challenges in four attributes: "Ionization degree," "Ionization equilibrium constant," "Solution acidity/alkalinity and pH," and "Acid-base titration". (3) The predominant learning path for students to construct a conceptual network is： Electrolyte → Strong /weak electrolyte → Ionization equilibrium → Ionization degree → Ionic product of water → The shift in ionization equilibrium → Ionization equilibrium constant → Solution acidity/alkalinity and pH → Acid-base titration.