Question

Two students crystallized 10g samples of benzoic acid from water, the first dissolving benzoic acid at 80 degrees C and filtering at 10 degrees C, the second dissolving the acid at 95 degrees C and filtering at 18 degrees C. Calculate the quantity of water each student was required to use and the maximum recovery of benzoic acid possible in each case. Thanks. And, the solubility of benzoic acid in water is 0.21g per 100mL H2O at 10 degrees C, 0.27g per 100 mL H2O at 18 degrees C, 2.75g per 100mL H2O at 80 degrees C and 6.80 g per 100mL H2O at 95 degrees C.

Answer 1

student 1-- here are the equations:
80C-->10g/x ml=2.75g/100ml solve for x= in ml?? this is quantity of H2O

then
10C -->y gms/x ml(from above)= .21g/100ml solve for y= in grams??

then
10g - y grams = max recovery of benzoic acid

student 2--
95C-->10g/x ml=6.8g/100ml solve for x= in ml??

then
18C--> y gms/x ml(from above)= .27g/100ml solve for y= in grams??

then
10g - y grams = max recovery of benzoic acid