All of the ammonium salts decompose, or break down upon heating at a molecular level. Another property of ammonium salts is that they have solubility in water. They dissolve in water and can be used for many different things. Ammonium chloride salt can be used for cleaning metal surfaces before soldering. One use of Ammonium Sulphate is use as a fertiliser. Ammonium nitrate is used in the manufacture of fire works, and ammonium carbonate is used as a smelling salt.