More separation techniques

• Filtration Separates Insoluble Solids from Liquids
• Crystallisation Separates Soluble Solids from Solutions
• Evaporation

  1. Pour the solution into an evaporating dish

  2. Slowly heat the solution

  3. The solvent will evaporate and the solution will get more concentrated

  4. Eventually it will start to form crystals
• Evaporation


  A way of separating a soluble solid from a solution, but can only be used if the solute does not decompose when heated
• Crystallisation

  1. Pour the solution into an evaporating dish

  2. Gently heat the solution

  3. Some of the solvent will evaporate and the solution will get more concentrated

  4. Once some of the solvent has evaporated, leave the solution to cool

  5. The solute will start to form crystals in the cold, highly concentrated solution
• Filtration and Crystallisation can be used to separate rock salt (a mixture of salt and sand)
• Separating rock salt

  1. Dissolve the rock salt in water

  2. Filter the mixture to remove the sand

  3. Evaporate the water to leave the pure salt crystals
• Melting points are the temperatures at which solids turn into liquids
• Boiling points increase as intermolecular forces between particles increases
• The boiling point is the temperature at which the vapour pressure of a liquid equals atmospheric pressure
• Boiling points are the temperature at which liquid turns into gas