1 - PRINCIPLES OF CHEMISTRY
Filtration -
- Separates insoluble solid from liquid
- Can be used in purification - solid impurities
Crystallisation -
- Separates soluble solid from solution
2.Heat solution - some solvent evaporates, solution gets more concentrated
3. Stop heating when crystals start to form
4. Remove dish from heat, put in warm place for rest of solvent to evaporate
5. Dry product - drying oven or desiccator
Separating rock salt -
- Mixture of salt and sand
- Salt and sand are compounds
- Salt = soluble - dissolves then forms as crystals
- Sand = insoluble - collects on filter paper
2. Dissolve in beaker and stir
3. Filter through filter paper in funnel - filtering
4. Evaporate in evaporating dish - crystallisation
Distillation -
1 - Simple distillation
- Separating out a liquid from a solution
- Not similar boiling points
- Can use to separate pure water from seawater - evaporate until just salt left in flask
2. Lowest boiling point evaporates
3. Vapour cooled, condenses and is collected
4. Rest of solution left in flask
2 - Fractional distillation
- Mixture of liquids
- Similar boiling points
- Used for fractional distillation of crude oil at a refinery
2. Fractionating column on top
3. Heat
4. Liquids evaporate at different temperatures
5. Lowest boiling point - when thermometer reaches its boiling point it will be a the top of the column
6. Condensing through tube and collects into test tubes
Chromatography -
- Separates out dyes
- Can help you identify dyes - compare to what you think it might be
- Different dyes move up the paper at different rates
2. Add spots of different dyes on the line at regular intervals
3. Put sheet in beaker of solvent, not touching the line (eg: water - depends on what is being tested, sometimes ethanol is needed)
4. Put lid on container - stop solvent evaporating
5. Solvent carries dye up the paper and separates colours within it
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