Kc

[Maya Johnson 2a]

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

[Chloe Little 3K]

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]

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]

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]

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

[Valerie Doan 3I]

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]

Yep! Kc uses molarity.

[Siwa Hwang 3G]

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

[Astha Sahoo 3I]

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]

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]

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]

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