[OwlieTheOwl]

When we combine something like salt (NaCl) and water, we don't describe the process as a synthesis or the product, "salt water," as a compound.  What is the difference between the synthesis of a compound such as alum and the production of a mixture or solution such as a salt water..?

[OwlieTheOwl]

Is it because synthesis meaning a chemical reaction has taken place in the formation of alum.  Verses no chemical reatcion takes place in the formation of salt + water, therefore its not called a synthesis?