Diffusion is the
gradual movement of particles from a high concentration to a lower
concentration.
Dilution of coloured
solution:
example- Potassium
Manganate(VII) and Water:
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Take a beaker of water and place some potassium manganate(VII) at the bottom, the purple colour will slowly spread out to fill the beaker
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The particles of the potassium manganate(VII) are diffusing out among the particles of water
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This is evidence of random motion of particles in a liquid that causes the purple colour to eventually be evenly spread out throughout the water
Diffusion
Experiments:
Ammonia and Hydrogen
Chlorine-
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Aqueous ammonia gives off ammonia gas and hydrochloric acid gives off hydrogen chloride gas
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When you set up the experiment a white ring will form of ammonium chloride in the glass tube
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The NH3 gas diffuses from one end of the tube and the HCl gas diffuses from the other. When they meet they form Ammonium chloride.
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The ring forms nearest to where the HCl gas was
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This is because the particles of ammonia are smaller and lighter than the particles of hydrogen chloride and so diffuse through the air quicker
Bromine gas and air-
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Bromine gas to brown and has a strong smell
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Fill half a gas jar full of bromine gas and the other half full of air- separate the gases with a glass plate
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When the glass plate is removed you'll see the brown bromine gas slowly diffuse through the air
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The random motion of the particles means that the bromine will eventually diffuse right through the air
Atoms are made up of
the nucleus (which contains protons and neutrons) and electrons which
move around the nucleus
Molecules are groups
of atoms
Elements consist of
only one atom
Compounds are
chemically bonded atoms
Mixtures are easily
separated compounds as there is no chemical bond between them
Separating of
mixtures:
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Filtration- used to separate an insoluble solid from a liquid
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Crystallisation- used to separate a soluble solid from a solution
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Chromatography- separate out mixtures, usually dyes. It works because different dyes move up the paper at different rates
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Simple distillation is used to separate out solutions using heat
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Fractional distillation is used to separate a mixture of liquids, for example crude oil