1. Assume 2.0 g of salicylic acid will be used. Calculate the moles of salicylic acid using its molar mass. 2. Use the mole ratio from the chemical equation to determine the ideal moles of acetic anhydride. Then multiply the answer by three to obtain an excess of the acetic anhydride. Convert the moles of acetic anhydride to mass in grams using its molar mass. 3. 4. Convert the mass to volume in mL using the density of acetic anhydride, which is 1.082 g/mL. Finally round the volume to the nearest 0.1 mL so it can be measured in the lab.