Energy Transfer in Reactions

This video explains what happens with energy transfer in reactions

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Breaking Bonds

  • Chemical reactions involve the making and breaking of bonds.
  • Energy must be taken in so that bonds can be broken.
  • Energy is given out when new bond are made.
  • EA is the activation energy this is the energy required to break the bond of the reactants.
  • AH is the energy (enthalpy) change of the reaction if it is negative energy is given out if it is positive energy is taken in.
  • In an exothermic reaction more energy is released making new bonds than is taken in breaking bonds.
  • In an endothermic reaction less energy is released making new bonds than is taken in breaking bonds.

The energy change of a reaction can be calculated using the following formula:

AH = Energy used in breaking bonds- Energy given out in making bonds

Remember for a particular bond the energy for breaking and making it is the same.

This video explains more about breaking bonds

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Southampton University
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