making salts

• SALTS are often created by reacting an ACID with a BASE.

  • To make a SOLUBLE salt from an INSOLUBLE base, you need to use the correct reactants.
• To make LITHIUM CHLORIDE, pick the correct BASE to give lithium & the correct acid to give chloride like:

  • Lithium Oxide & Hydrochloric Acid
  • Lithium Carbonate & Hydrochloric Acid

  
• • 83g at 80℃
  • 32g at 20℃
  • 83 - 32 = 51g

  
• • react hydrochloric acid with copper oxide in a suitable container
  • add copper oxide until solid remains
  • stir
  • filter excess copper oxide
  • pour solution into evaporating basin
  • use a water bath to heat gently
  • leave to cool

  
• How would the student know that excess copper oxide has been added?

  Black solid remains after stirring.

  
• Zinc oxide solid remaining.

  
• Excess zinc oxide is used rather than excess hydrochloric acid, cause excess zinc oxide can be filter off.

  
• To obtain crystals of zinc chloride from a solution of zinc chloride, leave the solution to cool.
• The solution should be heated gently by a boiling water bath or an electric heater.

  
• Step 2:

  • To speed up the reaction

  Step 5:

  • To make sure all the acid reacts or no crystals will be made

  Step 6:

  • To remove the excess magnesium oxide

  
• Soluble salt crystals from an acid-base reaction:

  • Place dilute acid in beaker & heat by a BUNSEN BURNER
  • Add solid base till it stops reacting, so it's in excess & acid's neutralised
  • Filter excess solid base with filter paper & funnel for dissolved form of the soluble salt
  • Heat salt solution to evaporate off some water in a water bath or electric heater than a Bunsen burner
  • To not risk heating the solution too much & damaging our salt, till crystals start forming
  • Let solution cool for more crystals to form
  • Filter the soluble salt crystals by filter paper & funnel
  • Dry crystals

  
• When a soluble salt is formed from an acid & an insoluble base, how do you know when an excess of base has been added?

  Some of the reactant will be left unreacted 
• Explain why this crystallization process works:

  The salt becomes less soluble in the water, as the solution cools, some cannot remain dissolved.