Salicylic Acid and Acetic Anhydride --> Acetylsalicylic Acid and Acetic Acid C7H6O3 + C4H6O3 --> C9H8O4 + C2H4O2 Salicylic Acid - 1.75g 1.6 equivalents of acetic anhydride for every equivalent of salicylic acid. Volume of salicylic acid = 1.22ml Molecular weight of salicylic acid = 138g/mol Mmol of salicylic acid = 12.7 mmols Density of salicylic acid = 1.44g/ml Acetic Anhydride - ?g Molecular weight of acetic anhydride = 102g/mol Density of acetic anhydride = 1.08g/ml What is the mass for acetic anhydride?