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### using Kp vs Kc

Posted: Fri Jan 10, 2020 12:31 pm
If all the reactants and products are in the gas phase, do you have to use Kp? Or can you use Kc?

### Re: using Kp vs Kc

Posted: Fri Jan 10, 2020 12:33 pm
If all of the reactants and products are in the gas phase, then you must use Kp if only the partial pressures are given. Kc* is used for concentrations, and is thus used when the reactants and products are in the aqueous phase. I think it depends on what you are given.

### Re: using Kp vs Kc

Posted: Fri Jan 10, 2020 12:35 pm
I think you should get the same number for both, but I'm not entirely sure.

### Re: using Kp vs Kc

Posted: Fri Jan 10, 2020 12:36 pm
*Kc can be used for when concentrations are being used, while Kp is more particular to partial pressures and is more specific to gases.

### Re: using Kp vs Kc

Posted: Fri Jan 10, 2020 4:00 pm
I think for an equation involving gases, either Kp or Kc can be used since you can convert from one to the other using the Ideal Gas Law.

### Re: using Kp vs Kc

Posted: Fri Jan 10, 2020 4:02 pm
Kp is for partial pressure, so when your products and reactants are in the gas phase. Kc is for concentration. However, for gases, you can use either Kc or Kp and just convert using the Ideal Gas Law.

### Re: using Kp vs Kc

Posted: Fri Jan 10, 2020 4:10 pm
you would use Kp if you are given the partial pressures.

### Re: using Kp vs Kc

Posted: Fri Jan 10, 2020 4:29 pm
Kp is used when you have the partial pressures of a gas, and Kc is used for concentration which can be found using PV=nRT

### Re: using Kp vs Kc

Posted: Fri Jan 10, 2020 4:54 pm
You can convert between Kp and Kc using the ideal gas law. Kp is used for partial pressures of gases, whereas Kc is used for concentrations.

### Re: using Kp vs Kc

Posted: Sat Jan 11, 2020 12:54 pm
You use Kp

### Re: using Kp vs Kc

Posted: Sat Jan 11, 2020 1:08 pm
Both can be used. Kc can be used when dealing with concentrations while Kp can be used when dealing with partial pressures. I believe the values will be the same.

### Re: using Kp vs Kc

Posted: Sat Jan 11, 2020 1:35 pm
You can use both but as everyone else mentioned, make sure to pay attention if you are given atms or mols.

### Re: using Kp vs Kc

Posted: Sat Jan 11, 2020 2:19 pm
If all the reactants and products are in the gas phase you would use Kp. Kp is for partial pressure when your reactants and products are in the gas phase. While Kc is for when concentrations are being used.

### Re: using Kp vs Kc

Posted: Sat Jan 11, 2020 2:43 pm
In fact, you can use both. Table 5G.2 shows an example of how Kc works for gas reactions.