If 150 mg of aspirin are rinsed with three portions of 10 mL of water at 25 degrees Celsius, how much aspirin is recovered? Solubility of aspirin in water at 25 degrees Celsius is one gram of aspirin per 300 mL of water.

Answer 1

Solubility is 1g aspirin in 300 mL.
So how much aspirin is lost with a 10 mL rinse and I use the term rinse lightly which I will comment on later.
1000 mg aspirin x 10mL/300 mL = 33.33 for the first rinse.
33.33 for the second rinse.
33.33 for the third rinse.
Total is 100 mg aspirin lost or 150 mg initially - 100 mg lost = 50 mg recovered.
Note about the rinse. If you "rinse" something you don't give it time to equilibrate so the solubility data may be misleading; i.e., in a rinse you don't give the solvent time enough to form a saturated solution. Therefore, you really don't lose this much aspirin; however, from the way the problem is worded I think the author expects rinse to be used in the sense that it dissolves all of the aspirin possible.