The vanadium in a sample of ore is converted to VO2. The VO2 ion is subsequently titrated with MnO4 in acidic solution to form V(OH)4 and manganese(II) ion. To titrate the solution, 26.45 mL of 0.02250 M MnO4 was required. If the mass percent of vanadium in the ore was 58.1%, what was the mass of the ore sample? Which of the four transition metal ions in this titration has the highest oxidation state?