The neutralization of a 0.455 g sample of recrystallized aspirin required 38.6 mL of 0.100 M NaOH solution. An additional 25.0 mL of 0.100 M NaOH was added to the sample to hydrolyze the neutralized aspirin in the solution. The solution was heated. Phenolphthalein was added to the cooled solution and was back-titrated with 11.2 mL of 0.100 M HCl. Determine the mass percent of the sample