Why is it not necessary to measure the volume of acetic anhydride to two significant figures and What is the theoretical yield of aspirin (in two significant figures).

Answer 1

Hi Johanna A.,

even without knowing anything more about your problem, I can say: you don't need to measure the volume of the acetic anhydride to two significant figures because you're adding it somewhat in excess, to force as complete a reaction of the salicylic acid as possible. To find the theoretical yield of aspirin, express your starting salicylic acid as moles. That's the same number of moles of aspirin you can maximally make, so multiply that by the molecular weight of aspirin to get the yield in grams. Done! With no headache (but even if you did get one, that's something aspirin can probably help with, you know ... Except for children: see Reye's Syndrome.)

-- Cheers, -- Mr. d.