Making 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 the main topic of the video from free science lessons?

  How to make a soluble salt using an acid
• What is an example of a soluble salt mentioned in the video?

  Copper sulfate
• What does every salt contain?

  A positive ion and a negative ion
• From where can the metal ion in a salt come?

  From the metal itself, metal oxide, metal hydroxide, or metal carbonate
• What is the positive ion in copper sulfate?

  The metal ion cu$^{2+}$
• Why can't copper sulfate be made by reacting copper with dilute sulfuric acid?

  Because copper is not reactive enough for that reaction
• What are the four sources of metal ions mentioned?

  Metal itself, metal oxide, metal hydroxide, metal carbonate
• 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 the acid will run out during the reaction
• What should be avoided when heating the acid?

  Allowing it to boil
• What should you do after adding copper oxide to the acid?

  Stir the solution using a glass rod
• What color indicates the formation of copper sulfate in the solution?

  Blue
• When should you stop adding copper oxide to the solution?

  When the solution turns clear blue and some powder remains
• What is the next step after the reaction has stopped?

  Filter away the unreacted copper oxide
• What equipment is used to filter the unreacted copper oxide?

  Filter funnel and filter paper
• What is the purpose of evaporation in the process?

  To concentrate the solution and form crystals
• How should the copper sulfate solution be heated during evaporation?

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

  24 hours in a cool place
• What should be done to the copper sulfate crystals after they form?

  Scrape them on a paper towel and gently pat them dry
• What is the final product of the process described in the video?

  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 the solution for 24 hours to allow crystals to form.
  6. Scrape and dry the crystals.
• What is the significance of ensuring no acid remains at the end of the reaction?

  • To prevent contamination of the salt.
  • To ensure the reaction is complete.
• What are the characteristics of copper oxide used in the experiment?

  • It is a black powder.
  • It reacts with dilute sulfuric acid to form copper sulfate.