Chemical Change

• Atom


  smallest particle that makes up everything
• Element


  one type of atom that make a substance
• Compound


  two or more elements chemically bonded in fixed ratios
• Mixture


  two or more elements or compounds that are not chemically bonded
• Molecule


  more than one atom joined together
• Exothermic reactions


  chemical reactions which release energy from the chemicals into the surroundings

  eg. combustion, respiration
• Endothermic reactions


  absorb energy from the surroundings

  eg. thermal decomposition
• Bases

  opposite of Acids, pH of 8 - 14:

  Soluble bases- Alkalis eg. metal hydroxide

  Insoluble bases- eg. metal oxide, metal carbonate
• Law of conservation of mass


  In a reaction, chemiccals react together to form new products, no atoms are lost in reaction

  mass cannot be created or destroyed
• Reactivity series:

  1. Potassium
  2. Sodium
  3. Calcium
  4. Magnesium
  5. Aluminium
  6. Carbon
  7. Zinc
  8. Iron
  9. Tin
  10. Lead
  11. Hydrogen
  12. Copper
  13. Silver
  14. Gold
  15. Platinum
• Extracted by electrolysis (reactivity order)

  Potassium, Sodium, Calcium, Magnesium, Aluminium
• Extracted by displacement (reactivity order)

  Zinc, Iron, Tin, Lead, Copper
• NO extraction needed as found native (reactivity order)

  Silver, Gold, Platinum
• Thermal decomposition


  breaking down of a compound using heat

  Metal carbonate -> metal oxide + carbon dioxde
• Combustion

  burning

  fuel + oxygen -> carbon dioxide + water
• Reaction of acids and metal

  metal + acids -> salt + hydrogen
• Reaction of acids and bases

  acid + base -> salt + water
• Reaction of acids and metal carbonates

  acid + metal carbonate -> salt + water + carbon dioxide
• Oxidation

  metal + oxygen -> metal dioxide
• Displacement 


  when a more reactive substance replaces the less reactive substance

  eg. Copper oxide + carbon -> Copper + carbon dioxide