Equilibria

Why do we omit solids and liquids in the equilibrium expression? I know it has something to do with concentrations, but I don't get it.
And for homogeneous equilibrium, why are the liquids and solids included in the equilibrium constant, when they aren't in heterogeneous equilibrium?

(edited 6 years ago)

Reply 1

SAMHANLEY88

solids and liquids are constants as their concentrations don't change through out the reaction
homogenous equilibria they aren't included in homogenous either :smile:

Reply 2

Mme_Bonii

Original post by SAMHANLEY88

solids and liquids are constants as their concentrations don't change through out the reaction
homogenous equilibria they aren't included in homogenous either :smile:

But what about this?

It was included in both my textbook and https://www.chemguide.co.uk/physical/equilibria/kc.html

(edited 6 years ago)

Reply 3

SAMHANLEY88

Original post by Mme_Bonii

But what about this?

It was included in both my textbook and https://www.chemguide.co.uk/physical/equilibria/kc.html

ok I was taught by teachers otherwise so I'm gonna assume it's because if they're all liquids they're all in a mixture so their concentration is a fraction of the mixture so when the reactants are used up then the concentration in relation to other reactants and products changes (I assume)

Reply 4

SAMHANLEY88

Original post by Mme_Bonii

But what about this?

It was included in both my textbook and https://www.chemguide.co.uk/physical/equilibria/kc.html

i didn't explain that well
the reason liquids and solids are emitted when there are aqueous or gases is because their change is negligible
whereas compared to eachother they become significant

Reply 5

Mme_Bonii

Original post by SAMHANLEY88

i didn't explain that well
the reason liquids and solids are emitted when there are aqueous or gases is because their change is negligible
whereas compared to eachother they become significant

Thank you so much!