{"knowledge_schema": {"broad_category": "Chemistry \u2192 Solutions \u2192 Concentration Calculations", "refinement": "This problem involves calculating the concentration of specific ions in a solution based on the dissociation of weak acids and their salts.", "specific_scope": "The focus is on determining the concentration of orthophosphate ions (PO4^3-) in a solution containing potassium dihydrogen phosphate (KH2PO4) and disodium hydrogen phosphate dihydrate (Na2HPO4\u00b72H2O).", "goal": "Calculate the concentration of orthophosphate ions in the solution using the provided masses, molar masses, and dissociation constants."}, "summary": "This problem is centered on chemistry, specifically the calculation of ion concentrations in a solution. It involves two phosphate salts, KH2PO4 and Na2HPO4\u00b72H2O, and requires understanding their dissociation in water to find the concentration of orthophosphate ions (PO4^3-). The solution's volume and the molar masses of the compounds are used to determine the moles of each salt, which are then related to the concentration of the orthophosphate ions. The final answer is 6.24x10^-7 M, indicating the concentration of orthophosphate ions in the solution."}