Question

 1. Compound X has a solubility in toluene of 18 mg per 100 mL at 20 °C, and a solubility of 0.64 g per 100 mL at 70 °C.

 You are given a sample of 0.48 g of compound X which is contaminated with 25 mg of compound Y.

 A. If compound Y is always soluble in toluene, describe in detail how you could separate Y from X. Would x now be pure?

 B. If compound Y has approximately the same values of solubility in toluene as compound x, describe how you could separate Y from X. Would X now be pure ?

 2. Each of the following compounds, B, C, and D, is equally soluble in the

 three solvents shown. In each case, choose which solvent you would use to purify the compound by recrystallization and explain your choice.

 Compound B : water, ethanol, and methanol

 Compound C : pentane, hexane, and toluene

 Compound D : acetone, diethyl ether, and ethanol

 3. The solubility of an unknown compound, J, in water is 16 mg per 100 mL at 20 °C and 0.72 g per 50 mL at 90 °C .

 A. Calculate the amount of water needed to recrystallize 1.6 g of compound J.

 B. Calculate the maximum amount of compound J recovered by filtration at 20 °C .

Answer 1