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How To Set Up GCSE Chemistry Required Practical – Making Salts – Copper Sulphate Crystals

How To Set Up GCSE Chemistry Required Practical – Making Salts – Copper Sulphate Crystals

In this short video, Emma Dent shows how to demonstrate the AQA Required Practical – Making Salts – making copper sulphate crystals.

Preparation of a pure, dry sample of a soluble salt from an insoluble oxide or carbonate using a Bunsen burner to heat dilute acid and a water bath, bunsen burner or electric heater to evaporate the solution.

This practical demonstrates first-hand how salts are formed through the reaction between an acid and a base, and the techniques involved in separating and purifying the salt product.

 

 

You will need:

  • 40cm3 1.0M dilute sulfuric acid
  • 5g copper (II) oxide powder
  • spatula
  • glass rod
  • 100cm3 beaker
  • 250cm3 beaker or water bath
  • Bunsen burner
  • tripod
  • gauze
  • heatproof mat
  • filter funnel and paper
  • small conical flask or small beaker
  • evaporating basin
  • crystallising dish or petri dish without lid
  • tongs
  • eye protection

 

Method:

  1. Begin by measuring 40cm³ of 1.0M sulfuric acid into a measuring cylinder and carefully pour it into the 100cm³ beaker.
  2. Set the 100cm³ beaker containing the sulfuric acid on the Bunsen burner using a tripod and gauze to ensure even heating and stability.
  3. Gently heat the sulfuric acid in the beaker until almost boiling. Exercise caution during this step to ensure safe handling of the equipment and turn off the Bunsen burner once finished.
  4. Use tongs to place the beaker on the heatproof mat. With the spatula gradually introduce small amounts of copper oxide powder to the heated sulfuric acid. Stir with the glass rod as you add it.
  5. Observe the reaction and continue adding copper oxide until no further effervescence is produced. The mixture will turn clear and blue.
  6. Fold and place filter paper inside a funnel to filter the blue copper sulfate solution into a conical flask (or a small beaker), effectively removing any excess copper oxide from the mixture.
  7. Transfer the filtered solution into the evaporating basin, taking care not to spill the contents.
  8. Place the evaporating basin over a 250cm3 beaker (or a water bath) and gently heat it
    to facilitate the evaporation process. Continue heating until you notice the initial formation of crystals within the solution.
  9. Test the solution by dipping a clean glass rod into the solution and waiting for it to cool. When small crystals form on the glass rod, stop heating the solution.
  10. Use the tongs to carefully pour into a crystallising dish (or petri dish without a lid) in a warm place for a minimum of 24 hours, allowing the crystals to fully crystallise.
  11. Once the crystals have formed, delicately pat them dry using two pieces of filter paper. Handle the crystals with care to avoid any damage during this process.

All health and safety measures are the responsibility of the teacher doing the demonstration. A thorough risk assessment should be carried out and guidance procedures followed. It is suggested that you practice before demonstration in front of a class.

 

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