CRP1

• The aim of this practical is to produce a pure, dry sample of a soluble salt from an insoluble oxide or carbonate.
• Filtration

  1. Filter the solution to remove the excess insoluble solid.

  • This will leave a solution of the salt dissolved in water.
• Crystallisation

  1. Heat the solution in an evaporating basin above a beaker of water.

  • The 'water bath' ensures gentle heating.

  1. Let the solution cool and allow more water to evaporate.

  • As water evaporates, the solution will become more concentrated and the salt will begin to crystallise.
• you can make soluble salts using an insoluble base
• you cannot make soluble salts using alkalis as alkalis are soluble
• soluble salts can be made from acids by reacting them with: metals, metal oxides, metal hydroxides or metal carbonates
• the right acid and right insoluble base must be used to produce the correct product
• what can you use to heat the solution?

  use a Bunsen burner to heat the dilute acid and then a water bath or electric heater to evaporate the solution
• what should you dry the crystals with?

  filter paper