Petrol and air sit side by side in a tank all day without burning; it takes a spark to push a few molecules over the activation-energy barrier Eₐ before the reaction starts at all. The higher the temperature, the larger the fraction of collisions hard enough to react, so the dominant direction flips sooner and the concentration curves steepen. A catalyst lowers Eₐ and the system reaches equilibrium far sooner, yet the position of that equilibrium does not move an inch and the constant K is unchanged. Shifting it for real takes adding or removing a substance, or changing the temperature, exactly as Le Chatelier’s principle says.
Petrol and air sit side by side in a tank all day without burning; it takes a spark to push a few molecules over the activation-energy barrier Eₐ before the reaction starts at all. The higher the temperature, the larger the fraction of collisions hard enough to react, so the dominant direction flips sooner and the concentration curves steepen. A catalyst lowers Eₐ and the system reaches equilibrium far sooner, yet the position of that equilibrium does not move an inch and the constant K is unchanged. Shifting it for real takes adding or removing a substance, or changing the temperature, exactly as Le Chatelier’s principle says.
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