Question

The solubility of benzoic acid in water is 0.21g per 100mL of water at 10 degree C, 0.27g per 100mL at 18 degree C,
2.75g per 100mL at 80 degree C
and 6.80g per 100 mL at 95 degree C.

Two students crystallized 10g samples of benzoic acid from water, the first dissolving benzoic acid at 80 degree C and filtering at 10 degrees C, the second dissolving the acid at 95 degree C and filtering at 18 degree C. Calculate the quantity of water each student was required to use and the maximum recovery of benzoic acid possible in each case.

Answer 1

old question but I'll attempt anyway so this can be closed

first student: starts w/ 10g and dissolves it at 80 degrees C. set up a proportion where

(10g/x mL) = (2.75g/100mL) since 2.75g/100mL is the solubility @ 80 degrees. then, use this volume, and the solubility at 10 degrees, to calculate how much of the benzene would still be dissolved at 10 degrees. then subtract this from the original amt. 10g to get the amount that would be solid.

repeat with the other student's #'s

Answer 2

*benzoic acid not benzene but you get the point

@dude can you double check me on this