← All parts of this equation

Equation 1 · Part 5 · Lowering the Barrier: What a Catalyst Actually Does

=

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

What this part means

The expressions on both sides represent the same quantity under the stated assumptions.

Its job in the formula

The equals sign connects the complete expression on the left with the complete expression on the right. Both sides must have compatible units.

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.

Read this part in the article →

Learn the underlying idea

An equals sign says that the expression on its left and the expression on its right have the same value under the stated definitions and assumptions.

Open the illustrated equality: what the equals sign claims guide →

The article lists its research sources here.