Stoichiometry Example You have been hired to work at a new pharmaceutical compan
ID: 1045214 • Letter: S
Question
Stoichiometry Example You have been hired to work at a new pharmaceutical company that starts synthesizing a new pain killer called Painlexx Your goal for this month is to produce 100 boxes of the new drug. Each box contains 25 pills. Each pill weights 0.5g. Each pill has only 5% of the active ingredient acetaminophen being everything else excipient. The synthesis of acetaminophen is indicated by the equation below. Please note the formula expressed in two different ways so you can calculate the molar mass. You have notes that remind you the reaction has a percentage yield of 73%. 0 CH, 0 CH,COH ?? C«H,NO2 acetaminophen OH CsH,NO C4H6O3 C2H402 acetic anhydride acetic acid Questions: How much p-aminophenol do you need to make all the pills need to meet your goal? When you get to your new lab, you find you have 50 grams of p-aminophenol, and access to any amount of acetyl anhydride you need. How many pills can you make with the amount you have? 1- 2- 3- The price of p-aminophenol is $100/g. Everything is very inexpensive in comparison. What would be the cost for each pill.Explanation / Answer
1-
We have to make = 100 x 25 x (0.5 x 0.05) = 62.5 g acetaminophen
with 73% yield
Theoretical yield would be = 62.5 x 100/73 = 85.62 g acetaminophen
mass p-aminophenol needed = (85.62 g/151.163 g/mol) x 109.14 g/mol = 61.82 g
2-
p-aminophenol = 50 g
with yield of reaction = 73%
acetaminophen formed from it = (50 g/109.14 g/mol) x 151.163 g/mol x 0.73 = 50.55 g
1 pill weighs 0.5 g and it has 5% active ingredient (acetaminophen)
1 pill has = 0.5 x 0.05 = 0.025 g acetaminophen
So, with 50.55 g acetaminophen we can make = 50.55 g/0.025 = 2022 pills
3-
price of p-aminophenol = $100/g
we have used = 50 g x $100/g = $5000 p-aminophenol here
109.14 g p-aminophenol gives 151.163 x 0.73 = 110.35 g acetaminophen
number of pills formed = 110.35 g/0.025 = 4414 pills
cost of pill (theoretical) = $5000/4414 = $1.133 per pill