Topic 1 - Mixtures and Separation Flashcards
What is a mixture?
Two or more substances joined together. (These can be elements or compounds).
There is a chemical bond between the different parts of a mixture. True or False?
False.
Give 3 examples of ways to separate mixtures.
Crystallisation, Filtration, Chromatography, Simple distillation, Fractional distillation, Evaporation.
Explain how chromatography works
1) Start by placing a line at the bottom of some filter paper (with a pencil) and draw dots of ink onto this.
2) Place this into a beaker of water or ethanol making sure the ink doesn’t touch the solvent.
3) Place a lid atop the beaker and you will see the ink moving up the paper. If the dye is insoluble then it will stay on the base line.
4) Take it out to dry and you will be left with a chromatogram.
Explain how filtration works.
1) Place a funnel (lined with filter paper) into an empty beaker.
2) Pour the solid and liquid mixture into the funnel and wait for the liquid to move into the beaker.
Explain how crystallisation works.
1) Pour the solvent into an evaporating dish and gently heat it
2) Once some of the solvent has evaporated, or when crystals start to form, remove the dish from the Bunsen burner.
3) Filter the crystals and leave them to dry.
Explain how simple distillation works.
1) Connect a condenser to a flask and place the solution inside. Then put a bung on top with a thermometer going into the flask.
2) Heat the solution so it evaporates and exits into the condenser to turn back into a liquid and drips into a beaker at the other end.
3) The salt from the solution will be left in the original flask.
Explain how fractional distillation.
1) Heat a water and ethanol solution in a flask until it evaporates and enter the fractionating column.
2) The different liquids evaporate at different times as they have different boiling points. Liquids with lower boiling points evaporate first.
3) The ethanol evaporates and condenses first and is left in the beaker. The water follows soon after.
