Water in equilibrium constants

Moderators: Chem_Mod, Chem_Admin

Megan_Ervin_1F
Posts: 78
Joined: Fri Sep 28, 2018 12:18 am

Water in equilibrium constants

Postby Megan_Ervin_1F » Tue Jan 08, 2019 11:28 am

Is water not counted in the chemical equilibrium constant? And if so, is this why liquids are not considered either since their concentrations are approximately water?

Fanny Lee 2K
Posts: 73
Joined: Fri Sep 28, 2018 12:29 am

Re: Water in equilibrium constants

Postby Fanny Lee 2K » Tue Jan 08, 2019 11:33 am

Pure liquids (such as the solvent water) are not considered in the k expression since there is such a large excess and the amount used in the reaction is a very small amount, we can say that the concentrations do not change significantly. If the concentrations were used to find the equilibrium constant, the values would cancel out and result in a ratio of 1:1.

Nicole Elhosni 2I
Posts: 62
Joined: Fri Sep 28, 2018 12:28 am

Re: Water in equilibrium constants

Postby Nicole Elhosni 2I » Tue Jan 08, 2019 11:42 am

How come water is included in the equilibrium constant when it is in the gaseous state? Is it because all gasses are included in the calculation when finding k?

Clarissa Cabil 1I
Posts: 66
Joined: Fri Sep 28, 2018 12:19 am

Re: Water in equilibrium constants

Postby Clarissa Cabil 1I » Tue Jan 08, 2019 11:53 am

Nicole Elhosni 2I wrote:How come water is included in the equilibrium constant when it is in the gaseous state? Is it because all gasses are included in the calculation when finding k?


Yes, I believe you are correct. It might also be because in this reaction, water is not acting as a solvent and, therefore, be included when calculating the equilibrium constant.

Brian Hom 2F
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

Re: Water in equilibrium constants

Postby Brian Hom 2F » Tue Jan 08, 2019 1:31 pm

You don't count water in the equilibrium constant as it is a pure liquid, and there is so much of it as a solvent that it doesn't matter the small amount that is lost in a chemical reaction.


Return to “Equilibrium Constants & Calculating Concentrations”

Who is online

Users browsing this forum: No registered users and 4 guests