A number of students had difficulty with the recrystallization process. Answer the following questions regarding this portion of the characterization.
(a) A solid forms in both a precipitation reaction (Binary Chemical Reactions) and in a recrystallization process. Describe the similarities of these observations, and explain why the two procedures are not the same at the ion-molecular level.
(b) A commercial source of aspirin often found in the South is BC Powder. This powder contains aspirin and caffeine.
i. Draw the structure of these two compounds.
ii. Use the Web to find the amount of aspirin and caffeine in a BC packet.
iii. Describe the types of intermolecular forces expected in these two compounds.
iv. Predict the solubility of these two compounds in water.
v. Develop a strategy to separate these two compounds on a tlc plate. Suggest properties of the stationary phase and the mobile phase that would allow for a good separation. Justify your choices.