Chemistry - Le Chatelier's principle: introduction
Le Chatelier's principle: introduction
Equilibrium systems represent a position of stability. However, being
dynamic, equilibrium can be upset. Upsets usually increase the rate of the
forward reaction relative to the reverse reaction or the rate of the
reverse reaction relative to the forward reaction.
Given that industrial processes focus on maximising the yield of product,
strategies that can increase the rate of the forward reaction relative to
the reverse reaction may be economically advantageous.
There are four main ways that a system at equilibrium can be upset. These
* changing temperature (the addition or removal of energy)
* adding more of one of the components (reactants or products) of the
* removing some of one of the components of the equilibrium system
* changing the pressure (or volume) of the equilibrium system
Equilibrium systems that are upset respond by counteracting the upset.
This involves the rates of forward and reverse reactions becoming equal
again, ie equilibrium being re-established.
It is possible to predict, qualitatively, the direction of shift of a
position of equilibrium under the influence of one or more of the above
changes by applying a principle first put forward by the French physical
chemist Henri-Louis Le Chatelier in 1884.
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