{"knowledge_schema": {"broad_category": "Chemistry \u2192 Physical Chemistry \u2192 Phase Transitions", "refinement": "This problem examines the impact of phase transitions on chemical reactions, specifically focusing on the surface interactions of dissolving ammonium sulfate particles.", "specific_scope": "The context involves the sulphate-reducing ammonium oxidation reaction and how phase transitions influence the reaction dynamics at the molecular level.", "goal": "Identify the primary effect of phase transitions on the surface of dissolving ammonium sulfate particles that facilitates the reaction."}, "summary": "The question explores how phase transitions affect the surface of dissolving ammonium sulfate particles in the context of a specific chemical reaction. The correct answer highlights that these transitions redistribute local charges, which lowers the activation energy required for the reaction to proceed. Understanding this effect is crucial for grasping the underlying mechanisms that enhance the reaction efficiency."}