A) on a molecular scale, describe how a crystal of alum differs from a crystal of potassium aluminum sulfate. b) when preforming stoichiometric calculations with alum, what do you need to do differently to calculate the number of moles of alum compared to potassium aluminum sulfate?

A. Since the alum has an additional 12H2O, therefore obviously it is a heavier compound.

The hydrated form (alum) has a molar mass of about 474.39, while the anhydrous form has a molar mass of 258.39 only.

I’m not quite sure but I believe that the alum has a monoclinic structure while the anhydrous form has a amorphous structure.

B.  In stoichiometric calculations, the main difference would be on the molar masses to be used in computing for moles from grams and vice versa.