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    Just a general question about enthalpy level diagrams.
    I am aware that enthalpy increases until reaching a maximum at the transition state then reducing until products are completely formed. I assume the initial increase in enthalpy is due to bonds breaking then the reduction is due to bond formation of the products. However, surely that would cause the transition state to be the species where all necessary bonds are broken, but the accepted definition of transition state/ activated complex is a species where bonds are being broken and formed. Can someone please explain this?
    Thanks.
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    (Original post by MEPS1996)
    Just a general question about enthalpy level diagrams.
    I am aware that enthalpy increases until reaching a maximum at the transition state then reducing until products are completely formed. I assume the initial increase in enthalpy is due to bonds breaking then the reduction is due to bond formation of the products. However, surely that would cause the transition state to be the species where all necessary bonds are broken, but the accepted definition of transition state/ activated complex is a species where bonds are being broken and formed. Can someone please explain this?
    Thanks.
    You can think of the transition state as being the approach of two particles in a collision. The interaction of electron clouds causes repulsions that raise the energy of the system. If the collision has enough kinetic energy the particles collide and bond reformation takes place.
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    Ok thanks. So the increase in energy is due to electron repulsion, NOT the breaking of bonds?
    thanks.
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    And the decrease in energy after the transition state is due to reduced electron repulsion, and the only time bonds are broken/ being made is during the transition state?
 
 
 
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