Question

I have a question that is based on this experiment, but I really don't understand how to extrapolate the data to answer the questions that asked, and I don't think I can answer the question. Can someone help me?

The Experiement

Find the actual mass of ASA (C₉H₈O₄) (K_a = 3.2 x 10^-4) in one tablet using a titration with standardized 0.100 mol/L NaOH_{(Aq). ­}NOTE: it states that an actual ASA tablet has an approximate mass of 500mg (0.5g), and the tablet is not pure ASA.

Step 1:Use 0.500g of a crushed ASA tablet

Step 2: Add 10mL of distilled water to a flask to dissolve the ASA

Step 3: Add an indicator to the flask

Step 4: Fill a burette with standardized NaOH_(aq) and place the flash under the stopcock of the burette

Step 6: Add the base to the flask in small amounts. Swirl the flask between additions of base.

Step 7: Stop adding base when the indicator has changed colour.

Step 8: Record the volume of base used

Step 9: Repeat the procedure as many times as needed to have three consistent volumes.

The data for observations of four titratons was:

Titration trial #	Volume of NaOH(aq) used in mL
1	18.1
2	17.9
3	12.4
4	18.0

The question asks me to Calculate the number of moles and the mass of ASA in one tablet. Determine the percentage of the original mass of tablet that was actually ASA. This would be the percent purity of the tablet and would give an indication of the amount of filler that was present in the tablet.