Final answer:
In total, 0.0198 moles of Na₂⁺₋HPO₄ will release 0.0594 moles of ions when dissolved in water, with each formula unit producing two sodium ions and one hydrogen phosphate ion.
Step-by-step explanation:
To determine how many total moles of ions are released when 0.0198 moles of Na₂⁺₋HPO₄ dissolves completely in water, we need to first identify the ions produced upon dissolution. Sodium dihydrogen phosphate (Na₂⁺₋HPO₄) dissociates into sodium ions (Na⁺) and hydrogen phosphate ions (HPO₄²⁻) in water.
Na₂⁺₋HPO₄(s) → 2Na⁺(aq) + HPO₄²⁻(aq)
Since each formula unit of Na₂⁺₋HPO₄ releases two sodium ions and one hydrogen phosphate ion, the total moles of ions produced are the sum of moles of sodium ions and moles of hydrogen phosphate ions.
Total moles of ions = Moles of Na⁺ + Moles of HPO₄²⁻
For 0.0198 moles of Na₂⁺₋HPO₄ we get:
Total moles of Na⁺ = 0.0198 moles * 2 = 0.0396 moles
Total moles of HPO₄²⁻ = 0.0198 moles * 1 = 0.0198 moles
Therefore, total moles of ions = 0.0396 + 0.0198 = 0.0594 moles