Equilibria
, Equilibria
Not all reactions occur in one direction, some are reversible.
Reversible reactions:
• Reversible reactions can only occur within a closed system, often a sealed vessel being
used to suggest this.
• Reversible reactions will react dynamic equilibrium, which is where the forward and
backwards reactions occur at equal rates. There will appear to be no change in the
equilibrium mixture because as the reactants react the products react and there appears to
be no change.
Conditions for equilibrium
• Can only be reached in a closed system
• Equilibrium can be approached from either direction and the final equilibrium position
will be the same
• It is a dynamic process: the forward reaction rate = backward reaction rate
• It takes time to reach equilibrium
• They show no macroscopic evidence of change
• At equilibrium the concentrations are not necessarily equal but the substances may remain
constant
↑ ·
Dynamic equilibrium is not archived
instantly, it takes time!
Concentration and dynamic equilibrium
When equilibrium is reached,
the concentration of the
reactants and products need to
be constant (they do NOT need
to be equal
Showing how dynamic equilibrium position lies
ad 2NO2 2 4
Here the equilibrium lies on the lefthand side NO2
due to being at concentration than N2O,
it a
higher
t
, Equilibria
Not all reactions occur in one direction, some are reversible.
Reversible reactions:
• Reversible reactions can only occur within a closed system, often a sealed vessel being
used to suggest this.
• Reversible reactions will react dynamic equilibrium, which is where the forward and
backwards reactions occur at equal rates. There will appear to be no change in the
equilibrium mixture because as the reactants react the products react and there appears to
be no change.
Conditions for equilibrium
• Can only be reached in a closed system
• Equilibrium can be approached from either direction and the final equilibrium position
will be the same
• It is a dynamic process: the forward reaction rate = backward reaction rate
• It takes time to reach equilibrium
• They show no macroscopic evidence of change
• At equilibrium the concentrations are not necessarily equal but the substances may remain
constant
↑ ·
Dynamic equilibrium is not archived
instantly, it takes time!
Concentration and dynamic equilibrium
When equilibrium is reached,
the concentration of the
reactants and products need to
be constant (they do NOT need
to be equal
Showing how dynamic equilibrium position lies
ad 2NO2 2 4
Here the equilibrium lies on the lefthand side NO2
due to being at concentration than N2O,
it a
higher
t
