Calculation help

1. To calculate the molarity of the permanganate solution using the known standard solution of sodium oxalate solution we use the net ionic equation below.

Using my example the H₂C₂O₄ has a known molarity of 0.250 M and 0.020 L and was placed in a flask to be titrated. The result was 0.0395 L of unknown MnO₄^- being used. We can now calculate the molarity of the MnO₄^-

0.250 M H₂C₂O₄ x 0.020 L = 0.00500 mol H₂C₂O₄

0.00500 mol H₂C₂O₄ x 2MnO₄-/5H₂C₂O₄ = 0.00200 mol MnO₄^-

0.00200 mol MnO₄^- / 0.0395 L MnO₄^- used = 0.051 M MnO₄^-

2, 3, 4 and 5 involve the equation below and is exactly the same as prelab question #2. Use it as a guide to calculate the mass of the iron in the sample and the percent of iron in your sample.

Theoretical percentages should be somewhere around 25%.