Organic lab help plz

Question

its a acetaminophen lab:

1) during the crystallization of acetaminophen, why was the mixture cooled in an ice bath?

2) why should you use a minimum amount of water to rinse the conical vial while transferring the purified acetaminpophen to the hirsch funnel?

3) if 0.130g of p-aminophenol is allowed to react with excess acetic anhydride, what is the theroretical yeild of acetaminophen in moles? in gram?

4) give two reasons, why the crude product in most reactions is not pure.

thank you

Answer 1

Cold temperatures decrease the solubility of the acetaminophen, causing more of the product to "fall out" of solution.

You want to use a liquid to carry the product out of the vial, but don't want to dissolve the product in the water, where you'd have to recrystallize it again.  Using a minimum amount of water minimizes the amount of product that gets dissolved.