[jnimagine]

When you're doing recrystallization, how do you predict what will happen when say vanillin is added to boiling water?
so..you'll know the melting point of vanillin and the boiling point of water... what do these tell us?

Also, for any compound, if you know the melting poing and solubility in water, how can you calculate the expected volume of hot water that would dissolve say 0.15g of the compoud??
I am so lost.. I have never learned about recrystallization before.... totally new!
Plz *delete me* Thanks   

[AWK]

For solubility a melting point is rather unimportant

[Two00proof]

Don't worry about the melting point.  The idea behind a recrystallization is that the compound that you want to purify has a low solubility in the chosen solvent at cold temperatures and a moderate to high solubility at elevated temperatures.  Normally you can't predict how much solvent is needed to dissolve a given amount of impure compound unless you already know what the solubility is at different temperatures.
If that is indeed known it's just a simple conversion of grams/mL to mL, and you should know how to do that.