The percent by mass of sodium oxalate in the 0.134 g sample is approximately 28.75%.
To calculate the percent by mass of sodium oxalate in the 0.134 g sample, follow these steps:
1. Determine the moles of potassium permanganate (KMnO₄):
- Molarity of KMnO₄ = 0.02269 M
- Volume = 17.12 ml = 0.01712 L
- Calculate moles of KMnO₄.
2. Use the balanced chemical equation:
The balanced equation for the reaction between potassium permanganate (KMnO₄) and sodium oxalate (Na₂C₂O₄) is:
5 moles of Na₂C₂O₄ + 2 moles of KMnO₄ → 5 moles of Na₂MnO₄ + 2 moles of CO₂ + 8 moles of H₂O
This equation shows that the ratio of moles of Na₂C₂O₄ to moles of KMnO₄ is 5:2.
3. Calculate moles of sodium oxalate (Na₂C₂O₄):
Moles of Na₂C₂O₄ = 5/2 × moles of KMnO₄.
4. Calculate the molar mass of sodium oxalate (Na₂C₂O₄):
The molar mass is the sum of the atomic masses of the elements in one mole of the compound.
5. Calculate the mass of sodium oxalate in the sample:
Mass of Na₂C₂O₄ = Moles of Na₂C₂O₄ × Molar mass of Na₂C₂O₄.
6. Calculate the percent by mass:
Percent by mass = (Mass of Na₂C₂O₄ / Total mass of the sample) × 100.
By performing these calculations, you should find that the percent by mass of sodium oxalate in the 0.134 g sample is approximately 28.75%.