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Equation 1 · Part 6 · Lowering the Barrier: What a Catalyst Actually Does

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ΔG∘=−RTln⁡K,\Delta G^{\circ} = -RT\ln K,
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What this part means

Capital delta attached to a quantity marks a difference between two values of that quantity; the article’s sign convention determines the order.

Its job in the formula

Capital delta attached to a quantity marks a difference between two values of that quantity; the article’s sign convention determines the order.

The passage around this formula

The reason is a bookkeeping identity rather than an empirical observation. The equilibrium constant is fixed by the standard Gibbs energy difference between reactants and products, ΔG∘=−RTln⁡K\Delta G^{\circ} = -RT\ln K. and that difference is a property of the two end states alone. A catalyst is present in the initial state and present again, unaltered, in the final state. It therefore cancels out of the difference. Any device that genuinely shifted an equilibrium while returning to its original condition would be a perpetual motion machine of the second kind, and could be operated in a loop to extract work from a single heat bath.

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Learn the underlying idea

Addition combines quantities; subtraction measures the signed difference between them. Parentheses show what is combined before the rest of the expression is evaluated.

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The article lists its research sources here.