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### Pressure Notation

Posted: Sun Jan 20, 2019 9:43 pm
When we are writing out the concentrations to find the k constant if not all the products and reactants are gases, do we still use the P notation?

### Re: Pressure Notation

Posted: Sun Jan 20, 2019 9:45 pm
If not all chemicals involved are gases, you probably should use molarity rather than partial pressure.

### Re: Pressure Notation

Posted: Sun Jan 20, 2019 10:30 pm
I think Kp is only used when the reaction only includes gases, so I would default to Kc

### Re: Pressure Notation

Posted: Sun Jan 20, 2019 10:33 pm
Kc is regarding molar concentrations whereas Kp is for homogeneous gas equilibria.

If in any case you're required to convert from Kp to Kc or vice versa, you can use the formula:
Kp=Kc(RT)^deltaN

### Re: Pressure Notation

Posted: Sun Jan 20, 2019 10:46 pm
When finding Kp, do you have to use a specific unit of pressure? Or can you use any?

### Re: Pressure Notation

Posted: Sun Jan 20, 2019 10:59 pm
Kp should not have any units because it is an activity. ^