Filtration, Evaporation, Crystallisation

• What techniques can separate solids from liquids?

  Filtration, evaporation, and crystallization
• What is a mixture of a liquid and an insoluble solid called?

  A mixture
• What do we call a liquid with a soluble solid dissolved in it?

  A solution
• In a solution, what is sodium chloride referred to as?

  Solute
• In a solution, what is water referred to as?

  Solvent
• What is the purpose of filtration in separating solids from liquids?

  To separate insoluble solids from liquids
• How does filter paper function in the filtration process?

  It allows liquids to pass but not solids
• What happens if a solid is soluble in a liquid during filtration?

  It cannot be filtered out
• What is the first step in the evaporation process?

  Place the solution in an evaporating dish
• What is the role of heating in the evaporation process?

  To cause the solvent to evaporate
• What is a potential issue with using evaporation to separate solids?

  Some solids may decompose when heated
• What is the alternative technique to evaporation for sensitive solids?

  Crystallization
• What is the first step in the crystallization process?

  Heat the solution gently
• Why do more crystals form as the solution cools in crystallization?

  Solids are less soluble at colder temperatures
• What is the final step after filtering crystals in crystallization?

  Dry the crystals
• What can be used to dry crystals after crystallization?

  Warm air or an oven
• What are the steps involved in the crystallization process?

  1. Heat the solution gently.
  2. Allow some solvent to evaporate.
  3. Stop heating when crystals start forming.
  4. Cool the solution to form more crystals.
  5. Filter out the crystals.
  6. Dry the crystals.
• Compare evaporation and crystallization as methods for separating solids from solutions.

  • Evaporation:
  • Quick and easy
  • Risk of thermal decomposition
  • Crystallization:
  • Slower process
  • Preserves solid integrity