[helpmepleaseplease]

If increasing/decreasing the concentration of an excess reactant(acetic anhydride) influenced the percentage yield of a product(aspirin) experimentally, how could this be explained??

I know that in theory, the excess shouldn't affect the yield- since it's the limiting that decides how much is produced. But is there any possible explanation for this result?

The results of my experiment shows a correlation between the concentration of acetic anhydride and the amount of aspirin yielded.
Did I do my experiment wrong by not purifying..? Or is there an explanation that could be made about this?

I was thinking maybe kinetics/equilibrium could explain this?? (increase in conc. of reactant leads to increase in rate of reaction- maybe under limited time, faster reaction could have led to more synthesis)

[wildfyr]

There is a rather famous concept named after a Frenchman that is what you are looking for. You have in fact essentially mentioned it in the last sentence of your post.

[Babcock_Hall]

Your comment is misleading in at least one way: the amount of the limiting reagent controls the theoretical yield only, not the actual yield.