Making soluble salts

• Why is making a soluble salt a required practical?

  It is highly likely that there will be a specific question on this in the exam
• What is an example of a soluble salt mentioned in the video?

  Copper sulfate
• What do all salts contain?

  A positive ion and a negative ion
• What is the positive ion in copper sulfate?

  The metal ion $Cu^{2+}$
• From where can the metal ion in a salt come?

  From the metal itself, metal oxide, metal hydroxide, or metal carbonate
• Why can't copper sulfate be made by reacting copper with dilute sulfuric acid?

  Because copper is not reactive enough for that reaction
• What is one source of the negative ion in salts?

  The acid used
• What is the negative ion in copper sulfate?

  The sulfate ion $SO_4^{2-}$
• What acid is used to make copper sulfate?

  Sulfuric acid
• What is the first step in making pure crystals of a soluble salt?

  Start with a fixed amount of dilute sulfuric acid
• Why is dilute sulfuric acid considered the limiting reactant?

  Because it will run out before the other reactants
• What should be avoided when heating the acid?

  Allowing it to boil
• What happens when copper oxide is added to the acid?

  It reacts and seems to disappear, turning the solution blue
• When should you stop adding copper oxide to the solution?

  When the solution is clear blue and no more copper oxide dissolves
• What is done to remove unreacted copper oxide from the solution?

  Filter it away using a filter funnel and filter paper
• What is the next step after filtering the solution?

  Evaporate the solution to form crystals
• How is the evaporation process carried out?

  Heat the solution gently over a beaker of boiling water
• How long should the solution be left to form crystals?

  24 hours
• What should be done after the crystals have formed?

  Scrape the crystals onto a paper towel and gently pat them dry
• What do you end up with after the process?

  Pure dry crystals of copper sulfate
• What are the steps involved in making pure crystals of a soluble salt like copper sulfate?

  1. Start with dilute sulfuric acid.
  2. Add copper oxide and stir until the solution turns blue.
  3. Filter out unreacted copper oxide.
  4. Evaporate the solution to form crystals.
  5. Leave for 24 hours to allow crystals to form.
  6. Scrape and dry the crystals.
• What equipment is needed to make a soluble salt?

  • Beaker
  • Spatula
  • Glass rod
  • Filter funnel
  • Filter paper
  • Evaporating basin