A solid substance A is soluble in water to the extent of 10 mg/mL of water at 25 degrees C and 100 mg/mL of water at 100 degrees C. You have a sample that contains 100 mg of A and an impurity B.

a.) Assuming that 2 mg of B is present along with 100 mg of A, describe how you could purify A if B had the same solubility behavior as A. Would one crystallization produce pure A?

b.) Assume that 25 mg of the impurity B is present along with 100 mg of A. Describe how you could purify A if B had the same solubility behavior as A. Each time, use the correct amount of water to just dissolve the solid. How many crystallizations would be needed to produce pure A? How much A would have been recovered when the crystallizations had been completed? Show your work (Use a separate page if necessary).

c.) How does the presence of impurity B affect the solubility behavior of solute A? Do the solubilities of the two substances add together? Can each of them be treated separately?