Units of the Equilibrium Constant
The dimensions carried by an equilibrium constant, determined by the change in the number of moles in the balanced equation.
Formula / equation
units = (mol/L)^Δn
Unit
Various
In depth
When the total stoichiometric coefficients are equal on both sides the constant is dimensionless; otherwise it carries units. Strictly the thermodynamic constant is always dimensionless because activities are ratios, so the units seen in practice are an artefact of using raw concentrations.
Examples in the real world
Kc for N₂O₄ ⇌ 2NO₂ has units of mol/L, while Kc for H₂ + I₂ ⇌ 2HI has none.