elements mixtures and compounds

• Element


  A substance that consists of one type of atom
• Element


  • It is a pure substance with a fixed chemical composition throughout
  • It cannot be broken down into any simpler type of matter by any physical or chemical means
• Compound

  A pure substance that is formed when two or more different elements are chemically combined
• Mixture


  An impure substance formed as a result of a physical change
• Mixtures


  • Soda
  • Wine
  • Vinegar
  • Soil
• Solution


  A homogenous mixture that is made up of a solute that is completely dissolved in a solvent
• Solute


  The substance being dissolved in the solvent
• Solvent


  The substance (usually a liquid) in which the solute is dissolved
• Solutions


  • Salt and water
  • Sugar and water
• Aqueous solution


  A solution formed by dissolving solutes in water
• Unsaturated solution


  A solution that has less than the maximum amount of solute and thus has more available space for a solute to dissolve in the solvent
• Saturated solution


  A solution that has the maximum amount of solute that can dissolve in the solvent at a given temperature
• Supersaturated solution


  A solution that has more solute than its normal solubility, i.e. an excess of solute in a solvent
• Unsaturated, saturated and supersaturated solutions

  • Bottled soda before opening (supersaturated)
  • Bottled soda after opening (saturated)
  • Bottled soda after going flat (unsaturated)
• Suspension


  A heterogeneous mixture in which the composition is not uniform throughout the mixture
• Suspensions


  • Sand and water
  • Oil and water
  • Muddy water
  • Flour and water
  • Vinegar salad dressings (vinaigrettes)
• Colloid or Colloidal Mixture


  A substance which is suspended throughout a solvent giving it a homogenous appearance
• Four industries that centered on farming

  • Sisal
  • Tomatoes
  • Pineapples
  • Citrus
• Wrecking


  The practice of taking valuables from a shipwreck found close to shore
• Wrecking was the first industry introduced in the Bahamas
• How Bahamians benefited from wrecking

  • They exported goods from wrecking
  • They gained large amounts of money from it
• Rules of the wrecking industry

  • All Bahamian men and boats needed registration to take part in wrecking
  • The first person to arrive at a wreck was made the wreck master
  • The amount each wrecker would earn from a wreck was laid down in the law
• Bahamians often extinguished warning lights or set up false beacons on treacherous rocks to wreck unsuspecting ships
• Wrecking declined


  • Due to the construction of lighthouses
  • Steam power replaced sails on ships, making it easier to maneuver through seas
• Sponge


  An animal that attaches itself to the sea floor
• Six commercially imported types of sponges

  • Wool Sponges
  • Reef Sponges
  • Hardhead Sponges
  • Yellow Sponges
  • Honey Comb Sponges
  • Grass Sponges
• Wool sponge


  Used for bathing and washing horses off
• Yellow sponges


  Used for general house cleaning
• Grass sponges


  Used for baths, washing walls before painting, washing cars
• Honey comb sponge


  Used for cosmetic and domestic purposes
• Reef sponge


  Used for cosmetic uses
• Hardheaded sponge


  Used for scrubbing floors
• Main sponging ground


  The Mud, west of Andros in the Great Bahama Bank
• Other sponging grounds


  • Long Island
  • Exuma
  • Abaco
• Sponging boats


  • The sponging fleet consisted of 600 large vessels, each carrying up to 5 small boats called dinghies which were operated by two or three men. Each vessel contained 10 men and a cook.
• Kraal


  A shallow water enclosure where the sponge would be soaked
• A kraal was visited once a week
• How sponges were sold

  They were taken to the Sponge Exchange in Nassau and sold to Greek Merchants using the silent auction method
• How sponges were processed

  1. The two men would get into a dinghy with a glass bucket to look for a good sponge bed

  2. They would hook the sponges and take them back to the boat to dry in the sun so they die

  3. After they would be taken to a kraal to soak and beaten and scraped to remove decayed matter, sand and rock
• How sponges were prepared for sale

  Before they were sold, they would be given a final cleaning and chipping and dying before they were sorted out and pressed into burlap covered bales