Chemistry help Aspirin Synthesis.. ASAP

I need help with this question, not sure on where to start.

Starting with 35.00 grams of salicylic acid and 28grams of acetic anhydride, give the limiting reagent and calculate the theoretical yeild. If 37.15g of aspirin is recovered, give the percent yield.

Can someone help me through this problem?

MW is molecular weight
SA is salicylic acid
AA is acetic anhydride


MW SA = 138.12 g mol−1

MW AA = 102.09 g mol−1

moles SA = 35/138.12 = 0.253 moles SA

moles AA = 28/102.09 = 0.272 moles AA

Note that the mole ratio AA/SA in the chemical equation for the reaction is 1.
See http://chemistry.about.com/od/demonstrat…
This means SA is the limiting reagent.

The MW of acetylsalicylic acid is 180.16 g mol−1. We are expecting 0.253 moles acetylsalicylic acid.

0.253 * 180.16 = 45.6 grams acetylsalicylic acid

100 * 37.15g /45.6g =% yield