Biology Forums - Study Force

Acetylsalicylic acid, known as ASA, is the most commonly used pharmaceutical drug, with over 10 000 t manufactured in North America every year. ASA, C8H702COOH(s), is an organic acid like acetic acid and reacts with strong bases such as sodium hydroxide in the same way that acetic acid does.
As part of your evalution, find the percent difference between your experimental averaged value for the mass of ASA in a sample tablet, and the value for the mass (in mg) that is listed on the product label (325mg).
PURPOSE: The purpose of this investigation is to use titration analysis techniques to accurately determine the ASA content of a cosumer product: a standard pain-relief tablet.
PROBLEM: What is the mass of ASA in a cosumer tablet?
DESIGN: An ASA tablet is dissolved in methanol and then titrated with standarized sodium hydroxide solution using phenolphthalein as the indicator.
EVIDENCE:
Final burette reading(ml) : trial 1(19ml), trial 2(30.7ml), trial 3(42.4ml), trial 4(46ml)
Initial burette reading(ml): trial 1(7), trial 2(19), trial 3(30.7), trial 4(34.1)
Volume of NaOH(aq) added(ml): trial 1(12), trial 2(11.7), trial 3(12.5), trial 4(11.9)
Final indicator color: pink for all
Trial 3 must be canceled due to high volume.
12.0 + 11.7 + 11.9 = 35.6 / 3 = 11.9 as volume for NaOH

I need help on finishing this lab asap!
The balanced equation is:
C8H7O2COOH + NaOH -> NaC8H7O2COO + HOH(H2O)
I need to find the mass. The concentration of NaOH is 0.150mol/L
HELP

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Thank you