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Peter Atkins says
In introductory chemistry, we meet the empirical rule of thumb known as Le Chatelier’s principle:
When a system at equilibrium is subjected to a disturbance, the composition of the system adjusts so as to tend to minimize the effect of the disturbance.
For instance, if a system is compressed, then the equilibrium position can be expected to shift in the direction that leads to a reduction in the number of molecules in the gas phase, for that tends to minimize the effect of compression.Le Chatelier’s principle, though, is only a rule of thumb, and to understand why reactions respond as they do, and to calculate the new equilibrium composition, we need to use thermodynamics.
That Le Chatelier’s principle, is only a rule of thumb, and thermodynamic calculations need to be done to determine new equilibria.
So are there any exceptions to this rule of thumb ??