Calculating K when there is multiple phases


Moderators: Chem_Mod, Chem_Admin

Phuong Tran 1G
Posts: 33
Joined: Sat Sep 14, 2019 12:16 am

Calculating K when there is multiple phases

Postby Phuong Tran 1G » Thu Jan 09, 2020 1:19 pm

What do you do when the equilibrium equation includes both aqueous and gas phases? Do you solve for each independently and somehow add them or do you convert?

Alice Ma 2K
Posts: 52
Joined: Wed Nov 13, 2019 12:26 am

Re: Calculating K when there is multiple phases

Postby Alice Ma 2K » Thu Jan 09, 2020 1:35 pm

You would have to convert the gaseous species into concentration using the Ideal Gas Law and find Kc. There is no way to find Kp because the aqueous species have no partial pressure.

Andrew Liang 1I
Posts: 105
Joined: Fri Aug 30, 2019 12:18 am

Re: Calculating K when there is multiple phases

Postby Andrew Liang 1I » Thu Jan 09, 2020 1:47 pm

I think in that case we would need to convert the gas to molar concentration using the equation: concentration= P/RT.

kim 2I
Posts: 105
Joined: Thu Jul 25, 2019 12:17 am

Re: Calculating K when there is multiple phases

Postby kim 2I » Thu Jan 09, 2020 2:21 pm

When calculating K, all the components should be in the same "form/units." Therefore, the concentration of the gas would have to be calculated using the Ideal Gas Law of PV=nRT (divide by V on both sides, moles (n) over V = concentration, therefore, conc=P/RT). Finally the Kc can be calculated: Kc=[products]/[reactants].

Amy Xiao 1I
Posts: 101
Joined: Sat Jul 20, 2019 12:15 am

Re: Calculating K when there is multiple phases

Postby Amy Xiao 1I » Fri Jan 10, 2020 12:07 am

Thank you for clarifying why aqueous solutions cannot have partial pressure; I was under the impression that you could convert either to partial pressure or concentration for each of them.


Return to “Ideal Gases”

Who is online

Users browsing this forum: No registered users and 0 guests