C3-Hardness of water

C3-Hardness of water

1. Soft water

   • Makes a nice lather with soap
     • No scum or scale
       • Cheaper - however no known health benefits

2. Hard water

   • Scum occurs when adding soap
     • Calcium and magnesium ions make the water hard
       • Reacts with soap to make scum which is insoluable
         • Need more soap to get a lather - more expensive
           • When heated, hard water forms scale (CaCO3) on the insides of pipes/kettles.
             • This reduces the efficiency and may need to be replaced. This can block pipes.
               • Rain falling on rocks such as limestone/chalk can dissolve compounds like MgSO4 (it is soluable)
                 • Goof for teeth and bones and less risk of hear disease.

3. Temporary hard water - Softened by heating. Caused by hydrogencarbonate ions

   • Permanent hard water - Can only be softened by removing/replacing calcium/magnesium ions
     • Caused by dissolved calcium sulfate.