Organic Chemistry - Extraction
posted by Camille on .
You have 100 mL of a solution of benzoic acid in water; the amount of benzoic acid in the solution is estimated to be about 0.30 g. The distribution coefficient of benzoic acid in diethyl ether and water is approximately 10. Calculate the amount of acid that would be left in the water solution after four 20-mL extractions with ether. Do the same calculation, using one 80-mL extraction with ether, to determine which method is more efficient.
Kd = 10
Bz = 0.3 in 100 mL H2O
4 20 mL portions ether extraction
fn = [1+kd*(Vo/Va)]^-n
Vo = 20
Va = 100
-n = -4
Solve for fn which is the fraction of benzoic acid remaining in the water layer after 4 extractions. You can go through the math but I found 0.0037 g benzoic acid remaining after four separate extractions.
After 1 extraction I found 0.033 in the water layer; obviously it's more effective with more extractions than with one large extraction.
Well in order to solve this you must first start by evaluating what 100 mL of benzoic acid will do when mixed with water. But more importantly what to do with water itself because without water in the world, there would be no life. Thus, since we drink water, we come to the conclusion to whether or not we should watch tv or play video games. I normally choose to play games because they're fun.
Hope this helps.