types

• Water can be soft or hard. Soap is used to tell difference
• Soft water lathers easily : hard water forms a scum and a poor lather when shaken with soap
• hard water creates scum first then lather -> wastes soap
• water hardness caused by dissolved magnesium ions + calcium ions. These are from dissolved minerals in the water ( like calcium sulfate)
• The magnesium + calcium ions in hard water react with soap forming layer of scum that prevents lather forming
• Two types of hard water:

  • Temporary
  • permenant
• Water with most bubbles and most easily produced = softest water
• Temporary is caused by dissolved magnesium hydrogen carbonate + calcium hydrogen carbonate
• Permanent hard water caused by magnesium sulfate / nitrate and calcium sulfate / nitrate
• advantages of hard water = reduced risk of heart disease

  beneficial to bones and teeth
• Disadvantages of hard water = wastes soap

  blocks pipes + makes kettles less efficient due to limescale