## Equilibrium constant for water

Haley Dveirin 1E
Posts: 101
Joined: Sat Jul 20, 2019 12:17 am

### Equilibrium constant for water

when writing the equilibrium constant for water, why do we omit [H20] from the expression?

sarahsalama2E
Posts: 164
Joined: Fri Aug 30, 2019 12:16 am

### Re: Equilibrium constant for water

you omit the h20 from the expression because its liquid and also the concentration unchanged.

Alex Tchekanov Dis 2k
Posts: 118
Joined: Sat Aug 24, 2019 12:16 am

### Re: Equilibrium constant for water

You also do this because the activity of water is said to be one and thus when you multiply by one, it does not change the K value

Brian Tangsombatvisit 1C
Posts: 119
Joined: Sat Aug 17, 2019 12:15 am

### Re: Equilibrium constant for water

H2O is a solvent, and we omit all solvents from the K expression since they will be in large excess compared to the concentrations of the other aqueous reactants and products. Its concentration will not change after equilibrium is met, so it is insignificant and can be omitted from the K expression.