Maximum % yield after recrystallization?

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classicfan
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Maximum % yield after recrystallization?

Post by classicfan »

Hello.

I am having trouble with a question in my textbook.

If I have an 8.3 g sample of acetanilide (Solubility => 0.53g/100mL at 25oC and 5.0g/100 mL at 100oC) that needs to be purified by recrystallization, then what is the maximum % yield that can be recovered (10% excess of solvent was used)?

I'm confused as to how I go about such a question, so if you could, please, hint at what path I am supposed to take, I'd greatly appreciate it.
expert
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Post by expert »

Obviously from 5 g you can recover 5 g - 0.53 g = 4.47 g from 100 ml of solvent.
Now proportionally calculate how much you can recover from 8.3 g and how much solvent without excess.
Calculate how much you've lost for this amount of solvent and take additional 10% of this amount from your useful product.
Calculate final yield.
Remember safety first! Check MSDS and consult with professionals before performing risky experiments.
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