Filtration, Evaporation and Crystallisation

• What techniques can be used to separate soluble and insoluble solids from liquids?

  Filtration, evaporation, and crystallization
• What is formed when a solid does not dissolve in a liquid?

  A mixture of a liquid and an insoluble solid
• What is an example of an insoluble solid in water?

  Sand
• What do we call a liquid that contains a soluble solid dissolved in it?


  A solution
• In a solution of sodium chloride in water, what is the solute?

  Sodium chloride
• What is the role of filter paper in the filtration process?

  To allow liquids to pass through while retaining solids
• What is the purpose of a filter funnel in filtration?


  To easily pour the mixture through the filter paper
• What happens to a soluble solid in a liquid during filtration?

  It cannot be filtered out because it is dissolved
• What is the first step in the evaporation process to separate a soluble solid from a liquid?


  Place the solution in an evaporating dish or crucible
• What is the purpose of heating the solution in evaporation?

  To cause the solvent to evaporate and concentrate the solution
• 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 separating solids that decompose when heated?

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

  Place the solution into an evaporation dish and heat it gently
• Why do more crystals form as the solution cools in crystallization?

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

  Dry the crystals by leaving them warm or using an oven
• What are the steps involved in the crystallization process?

  1. Place the solution in an evaporation dish and heat gently.
  2. Allow some solvent to evaporate and crystals to form.
  3. Stop heating and let the solution cool.
  4. Filter out the crystals using filter paper and funnel.
  5. Dry the crystals by leaving them warm or using an oven.
• What are the differences between filtration, evaporation, and crystallization?

  • Filtration: Separates insoluble solids from liquids using filter paper.
  • Evaporation: Removes solvent to leave behind solid, but may decompose some solids.
  • Crystallization: Forms crystals from a solution by cooling and gentle heating, preserving solid integrity.