What does CRC Handbook of Chemistry and Physics, the Merk Index, or another reference tell you about what it takes to remove the 12 water molecules from alum? Why do we often "forget" to include "•12H₂O" when we write the formula of alum or similar hydrated salts? Would it be better to write the formula as Al(H₂O)₆K(H₂O)₆(SO₄)₂? Comment on the other ways the formula could be written, such as AlH₂₄KO₂₀S₂ or AlK(SO₄)₂(H₂O)₁₂
