Chemistry Assignment

1. What is the purpose of recrystallization? 2. How are insoluble impurities removed during a recrystallization? 3. How are soluble impurities removed during a recrystallization? 4. What properties are desirable in a recrystallization solvent? 5. During a crystallization procedure the mass of the crude sample was 56.4 grams, and the mass of purified crystals was 45.3 grams. Calculate the percent recovery for this recrystallization procedure. 6. What can be done if a hot solution cools to room temperature with no crystallization occurring? 7. A student obtained 120% percent recovery after a recrystallization procedure, how is this possible? 8. Why do you need to heat the sample SLOWLY to record its melting point? Give at least two reasons. 9. How can the melting point of a sample indicate the presence of an organic impurity? 10. What would happen if the solvent chosen for recrystallization has a higher boiling point than the melting point of the compound being purified?