Given that 1g of Phenacetin requires 82mL of hot water to dissolve, or 1310mL of cold water (TY= 3.92g):
1) How much water will you need to recrystallize the theoretical yield?
2) How much product will be lost because of recrystallization?
1) You have 3.92g and 1g will disssolve in 82 mL; therefore,
3.92 x (82/1) = about 321 mL.
2) How much phenacetin will dissolve in 321 mL if 1g dissolves in 1310 cold?
1g x (321/1310) = about 0.25
So you would get back 3.92-025 = ?
I've estimated here and there; you need to go through it with your own figures.