Energy Level Diagrams Flashcards
An energy level diagram is a diagram that shows
shows the energies of the reactants, the transition state(s) and the products of the reaction as the reaction proceeds ( called ‘extent of the reaction’ below)
The transition state is a stage during the reaction at which
which chemical bonds are partially broken and formed
The transition state is very …………– a molecule in the transition state cannot be …………….and is higher in energy than the ……………………
unstable
isolated
reactants and products
The activation energy (Ea) is the energy needed to
reach the transition state
We can define the activation energy as ‘the minimum amount of energy needed for reactant molecules to have a successful collision and start the reaction’
In an exothermic reaction, the reactants are
higher in energy than the products
In an exothermic reaction, the reactants are higher in energy than the products
The reactants are therefore closer to the
closer in energy to the transition state
Do exothermic reactions or endothermic have lower activation energy and why
exothermic as The reactants are therefore closer in energy to the transition state
Endothermic reaction
In an endothermic reaction, the reactants are
lower in energy than the products
In an endothermic reaction, the reactants are lower in energy than the products
The reactants are therefore ……………. transition state
further away in energy to the transition state
why do endothermic reactions have higher activation energy
The reactants are therefore further away in energy to the transition state
This means that endothermic reactions have a higher activation energy compared to exothermic reactions
PRACTICE DRAWRING
The enthalpy change of the reaction is the energy difference from
reactants to products.
Remember: Label the axis of the energy level diagrams!
The activation energy is the energy difference from
energy difference from reactants to the transition state.
