Question

Aspirin synthesis and Analysis:

Calculate theoretical yield of ASA?
Used 3.5mL of acetic anhydride and 1.5g of salicylic acid.

Answer 1

This is a limiting reagent problem and you don't have enough information to work the problem. You have 3.5 mL acetic anhydride and you need to convert that to mols. You need the density of the acetic anhydride to convert 3.5 mL to grams.
Here is a site that will show you how to solve limiting reagent problems.
http://www.jiskha.com/science/chemistry/limiting_reagent_problem.html