Respuestas
Respuesta:
ENERGY DIAGRAMS AND TRANSITION STATES.
The energy difference between the reagents and the State of Transition (ET), called
Activated Complex Energy, G≠
, determines how quickly the reaction occurs. A
G≠
which implies a large difference between the Energy of the Reagents and the
ET energy results in a SLOW reaction, because there are few
molecules of the reagent that have enough energy to scale the Barrier
Energy. A G≠
small one results in a Rapid Reaction, because almost
all reaction molecules are energy-efficient enough to scale the
Energy Barrier.
Most organic reactions have a G≠
in the range of 10 to 35
kCal/mol.
A change in reaction conditions affects G≠
in two ways:
a) Modify the Energy level of the reagents:
Reducing the energy level, so that G≠
increases and R shrinks.
Increasing the energy level, so that G≠
shrinks and R increases.
b) Stabilization of the Transitional State reduces G≠
and it increases R
The Destabilization of the Transitional State increases G≠
and reduces R.
It is customary to use the terms Exothermic and Endothermic to refer to
reactions in which the G•
negative and positive respectively, although
thermodynamically this is not correct, as the terms refer to the change
atypical, and there are many substances that do not adapt to this simplification.
The following Figures present Hypothetical Reaction Energy Diagrams
for different situations:
a) Rapid Exothermic Reaction (G≠
low and G•
Negative
Explicación: