text: show calculation 625 mg tylenol contains 85% acetaminophen how many moles of acetaminophen are present? 151.17   the answer is 0.003514 mols acetaminophen. here are the calculations:    acet = acetaminophen    tyl=tylenol.  625 mg tyl (85 mg acet/100 mg tyl)*(1 g acet/1000 mg acet)*(1 mol acet/151.17 g acet) = 0.003514 mols acet.  the whole calculation can be done in one line of math using stoichiometry.