Chemistry

Chemistry

1. Salt

   • In hot countries, salt is extracted directly from the sea. In cold countries, there's not much sun, nor heat, and so it wouldn't allow the sun's heat to evaporate away the water
     • The sea water gets trapped in huge shallow pools, because the heat from the sun wouldn't be able to reach the bottom of a small deep pool.
   • SOLUTE- Salt SOLVENT- Water
   • The dangers of obtaining rock salt by mining, is that you use explosives and there is a danger of the land formation collapsing
   • EXPERIMENT
     • 1. Crush & Grind
       • 2. Place solid in beaker- half filled with water
         • 3. Heat gently and stir with a glass rod
           • 4. Pour contents through filter funnel and then collect filtrate in an evaporating dish
             • 5. Evaporate to dryness

2. Separating Funnel

   • Example: Oil & Water
     • The oil floats on water, and you can see globules of oil
       • 1. Pour mixture into separating funnel
         • 2. Put stopper on
           • 3. Invert funnel several times
             • 4. Remove stopper
               • 5. Open tap
                 • 6. More dense substances will collect at the bottom
                   • 7. Close tap when layer of less dense substance approaches

3. Oil & Water

   • Formed over millions of years ago
     • Remains of microscopic plants and animals that once lived in the sea
       • Died, and fell to the bottom and were then buried by sediments
         • Sediments kept the oxygen away and stopped decaying
           • The heat and pressure increased and turned to oil and gas
   • POLLUTION
     • Oil Slick- oil which has escaped from tankers, due to them being damaged
     • Detergents which are used to mix the oil and water, can sometimes harm the marine life
     • Oil Companies should have detergents, polystyrene, powdered chalk, booms and high-pressured jets as emergency equipment

4. Simple Distillation

   • Involves 2 processes; Evaporation & Condensation
     • Example: Ink & Water
       • 1. The solution is heated so that its liquid component evaporates and escapes as vapour
         • 2. The vapour is cooled and condensed into liquid
           • 3. The liquid is called the distillate
   • Used in perfume industry

5. Leibeg Condenser

   • More efficient than Simple Distillation
     • Better method of cooling the vapour
       • A tube for the vapour to pass through, surrounded by a wider tube, which is kept filled with cold water
         • The cold outer tube will condense the vapour in the inner tube
           • Cold water constantly passes in from the cold tap at the bottom end of the outer tube and out from the top end of the outer tube into the sink

6. Fractional Distillation

   • Crude Oil comes straight from the ground.
     • Fractional Distillation is the treatment of oil
       • The Treatment of oil takes place in Fractionating Towers
         • Hot steam is used to heat up the crude oil in the tower
           • Fractions are the parts of the crude oil that are removed from the tower
             • Light Fractions, come off at the top of the tower. They are gases and have low boiling points. E.g. Petroleum Gases
               • Medium Fractions, come off at the middle of the tower. They are liquids and have medium boiling points. E.g. Deisel
                 • Heavy Fractions, come off at the bottom of the tower. They are solids and have high boiling points. E.g. Bitumen

7. Chromatography

   • Is the technique that is used to separate small amounts of two or more solids which are soluble
     • Dyes and Inks often contain more than one colour that have been dissolved
       • The paper used is called a Chromatogram
         • There are three techniques;
           • Ascending Strip
           • Wick
           • Pipette