Question

A student titrating a sample of a powdered aspirin tablet to find out how much acetylsalicylic acid is in the sample finds that it requires 30.4 mL of a 0.0902M sodium hydroxide solution to neutralize the acid in the sample. How many milligrams of acetylsalicylic acid did the sample contain? Use the correct number of significant figures. Do not include units or your answer will be counted wrong.

Answer 1

number of moles of NaOH = (30.4 * 0.0902) / 1000

                                                = 0.002742 moles

1 mole of Aspirin needs 1 mole of NaOH

0.002742 moles of NaOH needs 0.002742 moles of Aspirin

mass of Aspirin tablet = 0.002742 * 180.157 = 0.49399 g

                                         = 0.494 ( for three significants)