Energy

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  • Created by: Jasmin
  • Created on: 09-05-13 19:13
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  • Can be measured by:
    • Energy
      • EXOTHERMIC
        • Gives out energy to surroundings, heat, rise in temp
        • Example: fuel burning
      • ENDOTHERMIC
        • Takes in energy from surroundings, heat, fall in temp
        • Example: photosynthesis
      • During chemical reactions old bonds break, new formed
        • Break bonds
          • Energy mut be supplied to break existing bonds: Endothermic
            • E required to break old bonds greater than energy released when new bonds formed
        • Form bonds
          • Energy released when new bonds formed
            • Energy released to form bonds greater than energy used in breaking old bonds
    • Chemical reaction by taking temp of reagents (make sure same)
      • Mix in polysytrene cup and measure temp of solution at end of reaction
        • Method works for reactions of solids with water and neutralisation reactions
    • Biggest problme with energy measurements is
      • Amount of energy lost surroundings - can be reduced by
        • Putting beaker into cotton wool more insulation
        • Put lid on cup to reduce energ lost by evaporation
  • Energy
    • EXOTHERMIC
      • Gives out energy to surroundings, heat, rise in temp
      • Example: fuel burning
    • ENDOTHERMIC
      • Takes in energy from surroundings, heat, fall in temp
      • Example: photosynthesis
    • During chemical reactions old bonds break, new formed
      • Break bonds
        • Energy mut be supplied to break existing bonds: Endothermic
          • E required to break old bonds greater than energy released when new bonds formed
      • Form bonds
        • Energy released when new bonds formed
          • Energy released to form bonds greater than energy used in breaking old bonds

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