ignoring solids & liquids for K

Moderators: Chem_Mod, Chem_Admin

ursulavictorino1K
Posts: 55
Joined: Sun Feb 17, 2019 12:15 am

ignoring solids & liquids for K

Postby ursulavictorino1K » Thu Jan 23, 2020 11:12 pm

If we are supposed to ignore solids and liquids when calculating K, why is it that in the example CaOH2(s) -> Ca2+(aq) + 2OH-(aq), we used the Ca2+ and OH-?

Tauhid Islam- 1H
Posts: 64
Joined: Fri Aug 02, 2019 12:15 am

Re: ignoring solids & liquids for K

Postby Tauhid Islam- 1H » Thu Jan 23, 2020 11:17 pm

I think it's because they are dissociated ions in the solution, and not solids or liquids. They are in an aqueous state meaning that the solid dissolved in the solvent (water i believe) and now exists as ions in the solvent.

Ryan Yoon 1L
Posts: 55
Joined: Mon Jul 01, 2019 12:15 am

Re: ignoring solids & liquids for K

Postby Ryan Yoon 1L » Thu Jan 23, 2020 11:19 pm

The Calcium Hydroxide is dissolved in water making it an aqueous solution.

ursulavictorino1K
Posts: 55
Joined: Sun Feb 17, 2019 12:15 am

Re: ignoring solids & liquids for K

Postby ursulavictorino1K » Tue Mar 17, 2020 12:48 am

So an aqueous solution isn't considered a liquid?

Jiyoon_Hwang_2I
Posts: 101
Joined: Sat Sep 14, 2019 12:17 am

Re: ignoring solids & liquids for K

Postby Jiyoon_Hwang_2I » Tue Mar 17, 2020 6:25 am

ursulavictorino1K wrote:So an aqueous solution isn't considered a liquid?


No, only pure liquids (l) and solids (s) are exempt from calculating k. Aqueous solutions describe a solution or mixture containing a solute dissolved in a solvent which is water.

Vuong_2F
Posts: 90
Joined: Sat Sep 14, 2019 12:17 am

Re: ignoring solids & liquids for K

Postby Vuong_2F » Tue Mar 17, 2020 10:46 pm

ursulavictorino1K wrote:So an aqueous solution isn't considered a liquid?

Yes, they are different. To sum it up, you would omit a species from the equilibrium expression if it's in a solid(s) or pure liquid (l) state. If they are in an aqueous (aq) or gas (g) state, then you would include the species in the equilibrium expression.

Gurmukhi Bevli 4G
Posts: 49
Joined: Wed Nov 14, 2018 12:20 am

Re: ignoring solids & liquids for K

Postby Gurmukhi Bevli 4G » Wed Mar 18, 2020 12:10 am

Since the Ca(OH)2 gets dissolved in water, it is an aqueous solution, which makes it included within the equilibrium constant calculation.

Jeremy_Guiman2E
Posts: 82
Joined: Fri Sep 28, 2018 12:29 am

Re: ignoring solids & liquids for K

Postby Jeremy_Guiman2E » Wed Mar 18, 2020 12:27 am

When ions dissociate in solution, they are considered aqueous and are therefore not considered solids/liquids.


Return to “Equilibrium Constants & Calculating Concentrations”

Who is online

Users browsing this forum: No registered users and 1 guest