Hard and Soft Water

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  • Created by: Uswa
  • Created on: 24-03-13 15:09
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  • Hard and Soft water
    • Soap
      • Soft water readily forms lather with soap
      • Hard water reacts with soap to form SCUM so more soap is needed
      • Soap less detergents don't form scum
    • Hard Water
      • Contains dissolved compounds, usually Mg or Ca
        • Compounds are dissolved when water comes in contact with rocks
      • Two types of hard water
        • PERMANENT hard water- remains hard when boiled
        • TEMPORARY hard water- softened by boiling
          • Because it contains hydrogen carbonate ions
            • That decompose when heated to produce carbonate ions
              • Which reacts with the Ca and Mg ions to form a precipitate
      • Evaluate
        • Benefits
          • Calcium compounds are
            • Good for development
            • Good for maintenance of bones and teeth
            • Helps reduce heart disease
        • Drawbacks
          • Increase costs, as more soap is needed
          • When temporary hard water is heated, it produces scale
            • Which reduced efficiency of kettles and heating systems
    • Hard water can be made soft by removing Ca and Mg ions, by
      • Adding Sodium Carbonate
        • Reacts with  Ca and Mg ions to form a precipitate
          • Calcium carbonate or magnesium carbonate
      • Commercial water softners, like ION EXCHANGE COLUMN
        • Contain hydrogen/sodium ions which replace the Ca and Mg ions as the hard water passes through the column


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