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Why does changing the total pressure of a system at equilibrium via reduction of the vessel volume by way of piston compression cause a shift in the equilibrium, but addition of an inert gas does not?
CO2(g) + C(s) -------> 2 CO(g)
If you injected an amount of helium gas into a reaction vessel of the above reaction at equilibrium, there would be no shift in equilibrium, even though the mole ratio of gases in uneven between products and reactants. You would think that the resulting total pressure increase would shift the reaction towards the reactant side a.k.a. the side with less moles of gas...but this does not happen.
However, if you compress the reaction in a piston, the shift does occur.
What gives?
CO2(g) + C(s) -------> 2 CO(g)
If you injected an amount of helium gas into a reaction vessel of the above reaction at equilibrium, there would be no shift in equilibrium, even though the mole ratio of gases in uneven between products and reactants. You would think that the resulting total pressure increase would shift the reaction towards the reactant side a.k.a. the side with less moles of gas...but this does not happen.
However, if you compress the reaction in a piston, the shift does occur.
What gives?