Solvents

[Shannon Asay 1C]

Why are solvents not included in the equilibrium expression equation?

[Michael Nguyen 1E]

Solvents are not included in the equilibrium constant equation because the concentration of a solvent does not change significantly in equilibrium reactions. There is such a large excess of solvent in these reactions that their concentration is essentially constant throughout the reaction.

[Emma Popescu 1L]

The change in solvent concentration is insignificant because it is in excess.

[Jainam Shah 4I]

The solvent will be in large excess in the reaction and is present on the left and right side of the chemical reaction numerically. Any change in the concentration will be very minimal so it nearly stays at a constant concentration.

[Caitlyn Tran 2E]

Another way to think of this is by seeing what happens if you do include the solvent when calculating the equilibrium constant. Since the solvent has a negligible change in concentration, the approximately same value would be included in both the numerator and the denominator, thus causing the concentration of the solvent to cancel out. This is why we just leave it out when calculating the equilibrium constant.

[Jialun Chen 4F]

Since the change in concentration of the solvent is negligible, we don't include them in the equilibrium expression.