You will be using 0.2 M NaOH as your titrant solution. Your first job is to predict how many milliliters (mL) you are EXPECTING to use for the 500mg tablet. Use the molar mass of aspirin as 180.17 g/mol for ALL future calculations where molar mass is needed.
How many moles would be present in a 500 mg tablet?
0.000556 mol
0.00278 mol
0.10 mol
0.000278 mol
Knowing that the mole ratio for the titration is 1 mol NaOH: 1 mol Asp, what volume of 0.2 M NaOH would be needed if the expected tablet is 500 mg?
0.0142 L or 14.2 mL
0.0278 L or 27.8 mL
0.000556 L or 0.556 mL
0.0139 L or 13.9 mL
The actual titration you performed used 0.0417 L of 0.2 M NaOH. How many moles of aspirin in your actual sample are present?
0.000834 mol Asp
0.00167 mol Asp
0.0167 mol Asp
0.00834 mol Asp
And finally, using your answer choice from #3, how many milligrams of aspirin was in the sample tablet from the same batch that made the person ill? [Note: If your answer from #3 is incorrect, but you do the calculation for this question correctly, I will count it as correct.]