Atoms

Atoms

1. Elements

   • Consist of ONE TYPE of ATOM only

2. Compounds

   • Are CHEMICALLY BONDED

3. Mixtures

   • EASILY separated - not like compounds

4. Experiments

   • Diffusion of Ammonia and Hydrogen Chloride Gases
     • 1. Put several pieces of indicator paper along a tube
       • 2. Soak one piece of cotton wool in one solution and onr in the other in the other solution
         • 3. Put each cotton wool at each end of the tube and then seal the ends with a bung
           • 4. Wait for a smoke ring to form inside the tube
             • See where the smoke ring forms.
               • If is in the middle then the particles are travelling at the same speed
               • If it is futher to one side of the tube then the one set of particles is quicker
   • Dilution of a coloured solution
     • 1. Place 10cm3 of water in a test tube
       • 2. Add one crystal of the solid
         • 3. Shake carefully to dissolve
           • 4. Transfer 1cm3 to another tube and make up to a total volume of 10cm3
             • 5. Repeat step (4) until you see you more colour
               • Each time you add water you are DILUTING the solution, so making it lighter

5. Separating of mixtures

   • Simple Distillation
     • Different liquids boil at different temperatures so you can heat one up to evaporate it and then you are left with the other one which boils at a higher temperature
   • Fractional Distillation
     • You have different liquids in the bottom, you heat it up and then have a tube near the top which is a cooling tube. This allows for the gas to then turn to a liquid and you can collect it.
   • Filtration
     • I you pour salty water through a filter it all goes through
       • Then you can evapourate the filtrate and salt crystals will be left behind
   • Crystallisation
     • Impure solids can be separated using this method
     • The impure mixture is first dissolved in a warm solvent
       • When the temperature falls the impure part of it stays in the solution and the pure solid is left.
   • Paper Chromatography
     • It is used to separate different colours in solutions.
       • The colours separate into bands on filter paper

6. An atom is the building block of all things

7. A molecule is a collection of atoms