Kc

Moderators: Chem_Mod, Chem_Admin

Maya Johnson 2a
Posts: 96
Joined: Wed Sep 30, 2020 9:47 pm

Kc

Postby Maya Johnson 2a » Thu Jan 07, 2021 7:52 pm

When we are using ICE for to find equilibrium values, do we always use molarity?

Chloe Little 3K
Posts: 100
Joined: Wed Sep 30, 2020 10:02 pm
Been upvoted: 1 time

Re: Kc

Postby Chloe Little 3K » Thu Jan 07, 2021 7:54 pm

I think typically the answer is yes because when we're using ICE tables, the goal is usually to find the concentrations in order to calculate Kc and so you'd want to use molarity for the table.

Sofia Azmat 1I
Posts: 52
Joined: Fri Aug 30, 2019 12:16 am

Re: Kc

Postby Sofia Azmat 1I » Thu Jan 07, 2021 8:40 pm

Yes. Also just to add on to the previous post, if you are not given molarity in the question itself for your initial values and you are instead given something like moles/L, you are required to convert them to molarities before inputting them into your ICE chart. And also if instead of Kc you were looking at Kp, you would have to use the appropriate pressure units for that :)

Andrew Yoon 3L
Posts: 92
Joined: Wed Sep 30, 2020 9:36 pm

Re: Kc

Postby Andrew Yoon 3L » Thu Jan 07, 2021 10:01 pm

For Kc, you would use the molar concentration of the substances in the system. If the question asked you to find the Kp, you would use partial pressures of the substances in the system.

Katie Nye 2F
Posts: 90
Joined: Wed Sep 30, 2020 9:55 pm

Re: Kc

Postby Katie Nye 2F » Thu Jan 07, 2021 10:20 pm

Yes, Kc is always calculated from molarity which is the concentration but Kp is always calculated by partial pressure.

Valerie Doan 3I
Posts: 98
Joined: Wed Sep 30, 2020 10:03 pm
Been upvoted: 1 time

Re: Kc

Postby Valerie Doan 3I » Thu Jan 07, 2021 10:27 pm

Yes, the units for concentration in Kc are mol/L. Note that if we are not given molarity, we can calculate that by doing n/v= P/RT. The n/v represents the molarity aka concentration of the reactant or product. n is the moles and v is the volume, hence the units are mol/L.

Jasmine Yi 1G
Posts: 90
Joined: Wed Sep 30, 2020 9:37 pm

Re: Kc

Postby Jasmine Yi 1G » Thu Jan 07, 2021 10:43 pm

Yep! Kc uses molarity.

Siwa Hwang 3G
Posts: 89
Joined: Wed Sep 30, 2020 9:48 pm

Re: Kc

Postby Siwa Hwang 3G » Thu Jan 07, 2021 11:02 pm

Is it possible to use partial pressure for ICE table or no?

Astha Sahoo 3I
Posts: 95
Joined: Wed Sep 30, 2020 9:52 pm
Been upvoted: 1 time

Re: Kc

Postby Astha Sahoo 3I » Thu Jan 07, 2021 11:07 pm

Siwa Hwang 3G wrote:Is it possible to use partial pressure for ICE table or no?


I haven't seen it done before yet, but I believe you can since the Kp equation is quite identical to the Kc one.

Lorraine Jiang 2C
Posts: 102
Joined: Wed Sep 30, 2020 9:54 pm
Been upvoted: 1 time

Re: Kc

Postby Lorraine Jiang 2C » Fri Jan 08, 2021 6:19 am

Yep! I think we always use molarity to calculate Kc. For partial pressure, I think the same logic applies to Kp although I didn't see much examples on this topic.

Hope it helps!

Trevor_Ramsey_3H
Posts: 99
Joined: Wed Sep 30, 2020 9:58 pm

Re: Kc

Postby Trevor_Ramsey_3H » Fri Jan 08, 2021 9:40 am

Hi going off the Kp discussion, I believe Professor has been going over that you use partial pressure for gases and it is the same process as calculating Kc or using an ICE table.

Carly_Lipschitz_3H
Posts: 93
Joined: Wed Sep 30, 2020 9:56 pm

Re: Kc

Postby Carly_Lipschitz_3H » Sat Jan 09, 2021 4:48 pm

Yes, you're right! We always use molarity when doing ICE tables.


Return to “Equilibrium Constants & Calculating Concentrations”

Who is online

Users browsing this forum: No registered users and 3 guests