Question

solubilty of X in 100 ml solvent 0 C (water 2.7g) (ethanol 1.4g)

Solubility of X in 100 ml solvent at boiling point of solvent (water 15.7g) (ethanol 24.0g)

1.ml of boiling solvent required to disolve 25g of X

2.g of X that will remain soluable in this amount of solvent when cooled to 0C

3. g of X that will crstallize from the volume of solvent used in (a) when cooled to 0 C

4. % recovery of X for each solvent

Answer 1

Density of water is consider = 1g/cc and density of ethanol = 0.789g/cc

1. amount of boiling water required to dissolve 25g X = (100 x 25)/15.7 = 159.24 ml

  amount of boiling ethanol required to dissolve 25g X = (100 x 25)/24 = 104.17 ml

2. amount of X that will be remain soluable in water when cooled to 0C = (2.7 x 159.24)/100 = 4.30g

  amount of X that will be remain soluable in ethanol when cooled to 0C =  (1.4 x 104.17)/100 = 1.46g

3. amount that can be crystallized in water = 25 - 4.30 = 20.70g

  amount that can be crystallized in ethanol = 25 - 1.46 = 23.54g

4. % recovery of X in water = (20.7/25.0) x 100 = 82.8

  % recovery of X in ethanol = (23.54/25.0) x 100 = 94.16