Chemical changes

• Reactivity of a metal: how chemically reactive it is, how readily it forms an ion
• Reactivity series

  Potassium

  Sodium

  Lithium

  Calcium

  Magnesium

  Aluminium

  Carbon

  Zinc

  Iron

  Tin

  Lead

  Hydrogen

  Copper

  Silver

  Gold
• Ore: Rock containing enough of a metal compound to be economically worth extracting
• In terms of oxygen, what is oxidation and reduction

  Oxidation: Addition of oxygen

  Reduction: Removal of oxygen
• Reduction with carbon: How metals less reactive than carbon are extracted
• Electrolysis: How metals more reactive than carbon are extracted
• How are very unreactive metals extracted

  Mined from the Earths crust

  Silver and gold
• In terms of electrons, what is oxidation and reduction

  Oxidation: Loss of electrons

  Reduction: Gain of electrons
• Displacement reaction: Where a more reactive element takes the place of a less reactive element in a compound
• Spectator ion: Ion that is unchanged in a reaction
• Ionic equation

  An equation that shows what atoms/ions in a reaction are being reduced and oxidised
• Half equation

  Equation that shows what is happening to 1 element in a chemical reaction
• In terms of pH, what is an acid, a neutral solution, and an alkaline

  Acid: Solution with a pH less than 7

  Neutral solution: Solution with a pH of 7

  Alkaline: Solution with a pH higher than 7
• pH indicators

  Universal indicator tells us the approximate pH

  pH metres give us the exact pH of a solution
• Strong and weak acids

  Strong acids: Acids where molecules completely ionise in water

  Weak acids: Acids where molecules partially ionise in water
• A salt: A compound formed when a metal ion takes the place of a hydrogen ion in an acid
• A base: A substance that reacts with acids in neutralisation reactions
• What is an alkali

  a substance that dissolves in water to form a solution above ph 7
• Neutralisation reaction: A reaction between an acid and a base to produce water
• Crystallisation

  1. Choose correct acid and base to produce the salt
  2. Put some of the dilute acid into a flask, heat gently with Bunsen burner
  3. Add a small amount of base and stir
  4. Keep adding the base until no more reacts
  5. Filter to remove the unreacted base
  6. Add the remaining solution to an evaporating dish
  7. Use a water bath or electric heater to evaporate the water, the salt crystals will be left behind
• Electrolysis: The process of using electricity to extract elements from a compound
• Anode

  Positive electrode

  Electrons are lost

  Where pure non-metals are formed
• Cathode

  Negative electrode

  Electrons are gained

  Where metals are formed
• Electrolyte: Liquid or solution that contains ions and so can conduct electricity
• Where are non metals formed

  Anode
• How can ionic substances be electrolysed

  By melting or dissolving them, then passing a direct current through them
• Why can solid ionic substances not be electrolysed

  They do not conduct electricity, or the ions cannot move
• Half equation

  Equation which shows us what is happening to one element in a chemical reaction