posted by leah on .
An aspirin tablet weighing 0.475 g has been analyzed and contains 68.2 % ASA (180.16 g/mol) by mass. A student dissolved
the tablet in hot NaOH and the cooled solution was diluted with DI water to the mark in a 250 mL volumetric flask. Exactly 3.00 mL
of the solution was pipetted into a 100 mL volumetric flask and diluted to the mark with FeCl3 solution.
The concentration of the diluted solution is
0.475 g aspirin x 0.682 = g ASA.
That amount was placed in 250 mL beaker so the concn (in grams) = g ASA/250 mL.
Perform that division and you have g ASA/mL. Now you dilute it 3:100; therefore, the new concn is
g ASA/mL x (3 mL/100 mL) = g ASA/mL in the new solution. If you want molarity, you will need to convert to moles/L.