Measuring Aspirin Product

We got to use our knowledge of converting grams to moles into practice through our aspirin lab. First, we had to finish getting all the of the measurements that we needed. The only one that we had left to weigh was the dried Acetylsalicylic acid (the crystals that we let to dry during break). We trasferred the crystals to the balance and weighed the substance. Our group got 5.4766g of substance which included the mass of the filter paper. Mrs. Frankenberg then told us that we need to convert our starting material and ending material's masses into moles. Using everything we had learned the last few days, I was able to complete this assignment without trouble. My work is shown below:

http://vignette2.wikia.nocookie.net/sciencemadness/images/2/21/Acetylsalicylic_acid.JPG/revision/latest?cb=20140919033453

Molar Mass of Salicylic Acid (C₇H₆O₃):

(7*12.01)+(6*1.01)+(3*16.00)=138.13 g/mol C₇H₆O₃

Salicylic Acid in Moles:

5.1444g C₇H₆O₃ x (1 mole C₇H₆O₃/138.13 g C₇H₆O₃) = .037243 moles C₇H₆O₃

Mass of Acetylsalicylic Acid:

5.4766g (Acetylsalicylic Acid + filterpater)- .4074g (filter paper)= 5.0692g Acetylsalicylic Acid

Molar Mass of Acetylsalicylic Acid (C₉H₈O₄):

(9*12.01)+(8*1.01)+(4*16.00)=180.17 g/mol C₉H₈O₄

Acetylsalicylic Acid in Moles:

5.0692g C₉H₈O₄ x (1 mole C₉H₈O₄/180.17g C₉H₈O₄)=.028135 moles C₉H₈O₄

I checked my work using this website: Endmemo