Chemical changes

• Metal + oxygen = metal oxide
• Oxidation is gain of oxygen and loss of electrons
• Reduction is loss of oxygen but gain of electrons
• Reactivity series

  1. potassium
  2. sodium
  3. lithium
  4. calcium
  5. carbon
  6. magnesium
  7. aluminium
  8. zinc
  9. iron
  10. hydrogen
  11. tin
  12. lead
  13. hydrogen
  14. copper
• Metal + acid = salt + hydrogen
• Metals less reactive that carbon can be extracted using carbon
• Acids are neutralised by alkalis and based to form salt and water
• Acid + alkali = salt + water
• Acid + base = salt + water
• Acids are neutralised by metal carbonates to produce salt, water and carbon dioxide
• Acid + metal carbonate = salt + water + carbon dioxide
• Hydrochloric acid produces chlorides (…Cl)
• Nitric acid produces nitrates (…NO3) which are used to make amino acids
• Sulfuric acids produce sulfates (…SO4)
• Soluble salts can be made from acids by reacting them with solid insoluble substances
• Acids produce H+ ions in aqueous solutions
• Alkalis prodce OH- ions in aqueous soluions
• Neutralisation

  H+(aq) + OH-(aq) —> H2O (l)
• Soluble salts

  • Add chosen solid insoluble substance to acid and dissolve
  • Acid is neutralised when excess solid sinks to bottom, keep adding until
  • Filter, evaporate some water and leave the rest to evaporate slowly
• Electrolysis: passing a current through substances that are molten or solutions so they can be broken down into elements
• The substance being broken down is electrolyte
• + ions —> - electrode (cathode)
• -ions —> + electrode (anode)
• Aluminium mixed with cyrolite to lower the melting point
• Anode

  X- —> e- + X
• Cathode

  X+ + e- —> X