An unknown mass of Na₂O (molar mass = 61.979 g/mol) was dissolved in enough water to create a 100.0 mL stock solution. A 5.00 mL sample of the stock solution was transferred to a volumetric flask and diluted to 500.0 mL. The pH of the dilute solution is 13.03.
- Calculate the concentration of OH⁻ ions in the dilute solution.
- Calculate the concentration of OH⁻ ions in the stock solution.
- Determine the original mass of Na₂O dissolved in the stock solution.