This is an organic chemistry post lab report question.
Also, if you know about recrystallization, benzoic acid has a solubility of 68g/L in 95 C water. What is the min. volume of water it would take to dissolve 10 grams of benzoic acid at 95 C?
2007-09-29 05:11:16 · 4 answers · asked by Samantha 4 in Science & Mathematics ➔ Chemistry
Eileen, actually I'm pretty bad at math. I know that it is a conversion problem. And yes i know that there is no such thing as more than 100% recovery, but it is a post lab question.
I did 69g/1000ml=10g/xml and got .0068ml which doesn't make sense. I know it's somewhere close to 150ml through estimation....
2007-09-29 05:35:56 · update #1
This depends on what kind of procedures you were using. If your final product is a crystal or powder, then it may have some solvent in it because it is not completely dry, or it could have other compounds mixed in. Other possibilities are a calculation error on your part, or some other error, like a weighing error. In o. chem labs, you are almost always going to get much less than 100% recovery.
The second question is a conversion and you should be able to handle it by now if you are in o. chem.
68g/L=10g/xL Solve for X
xL=10g*L/68g= ...
2007-09-29 05:23:45 · answer #1 · answered by jellybeanchick 7 · 1⤊ 3⤋
>100% yield: Either your product is impure, or it hasn't benn dried properly and so still contains some solvent, which will increase the weight of the compound. For a carboxylic acid (eg benzoic acid), another possibility is that you haven't isolated the free acid (R-CO2H) but a salt (eg R-CO2Na) - this would have a significantly larger mass than the free acid, and so would give >100% recovery if calculated w.r.t the free acid.
Your solubility issue: If 68 g dissolves in 1000 ml, then 1 g will dissolve in (1000/68) ml. THerefore 10g will dissolve in 10 x (1000/68) ml
2007-09-29 06:10:33 · answer #2 · answered by LabMonkey 3 · 5⤊ 0⤋
God loves you, or you have a mistake in the amount of reagents, or your product isn't pure.
By proportion,
68 g/1000 ml = 10g/ X ml and solve for X.
2007-09-29 05:25:34 · answer #3 · answered by cattbarf 7 · 2⤊ 4⤋
I don't know the answer to the mixture problem.
I do know that there is NO SUCH % over 100%. I challenge your teacher to prove me wrong.
¦<)
2007-09-29 05:26:58 · answer #4 · answered by Anonymous · 1⤊ 13⤋