Example: 

salicylic acid + acetic anhydride « acetylsalicylic acid (ASA) + acetic acid

Salicylic acid:  (0.211 g) / (138.1 g/mol) * 1 = 0.00153 mol

Acetic anhydride:  (0.480 mL) * (1.08 g/mL) / (102.1 g/mol) * 1 = 0.00508 mol

Therefore, salicylic acid is the limiting reagent, since there are less moles of that than there are of acetic anhydride.