Asample of an iron ore is dissolved in acid, and the iron is converted to fe2+. the sample is then titrated with 47.20 ml of 0.02240 m mno4– solution. the oxidation-reduction reaction that occurs during titration is(a) how many moles of mno4– were added to the solution? (b) how many moles of fe2+ were in the sample? (c) how many grams of iron were in the sample? (d) if the sample had a mass of 0.8890 g, what is the percentage of iron in the sample?