Question

Organic chemistry help?

2. Eight grams of compound Y was recrystallized using the minimal amount of boiling water, 103 mL. In a separate experiment, a minimum of 50 mL boiling water was used to dissolve another sample of compound Y. After recrystallization at 20 °C, 95.7% of compound Y was recovered. Calculate the solubility of compound Y in water at 100 oC and 20 oC. (1 pt)

Answer 1

m = 8 g of Y

V = 103 mL

S = 8/103 = 0.077669 g /mL at T = 100°C

for the second crystallisation:

50 mL --> 0.077669*50 = 3.88345 g of salt should be in solution

then, after crystallisation,

0.957*3.88345 = 3.7164 g were recovered, meaning that

3.88345 -3.7164 = 0.16705 g are in solution

so

S2 = mass/V = 0.16705/50 = 0.003341 g /mL

Solubility at 100°C -->  0.077669 g /mL

Solubility at 20°C --> 0.003341 g /mL