## using Kp vs Kc

Clarice Chui 2C
Posts: 101
Joined: Fri Aug 30, 2019 12:16 am

### using Kp vs Kc

If all the reactants and products are in the gas phase, do you have to use Kp? Or can you use Kc?

Charysa Santos 4G
Posts: 107
Joined: Wed Sep 18, 2019 12:21 am

### Re: using Kp vs Kc

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.
Last edited by Charysa Santos 4G on Fri Jan 10, 2020 12:37 pm, edited 1 time in total.

Maia_Jackson_2C
Posts: 101
Joined: Fri Aug 30, 2019 12:17 am

### Re: using Kp vs Kc

I think you should get the same number for both, but I'm not entirely sure.

Charysa Santos 4G
Posts: 107
Joined: Wed Sep 18, 2019 12:21 am

### Re: using Kp vs Kc

*Kc can be used for when concentrations are being used, while Kp is more particular to partial pressures and is more specific to gases.

Katie Kyan 2K
Posts: 106
Joined: Fri Aug 09, 2019 12:16 am
Been upvoted: 1 time

### Re: using Kp vs Kc

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.

Hannah Pham
Posts: 104
Joined: Fri Aug 09, 2019 12:17 am

### Re: using Kp vs Kc

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.

Sally Qiu 2E
Posts: 105
Joined: Fri Aug 30, 2019 12:18 am

### Re: using Kp vs Kc

you would use Kp if you are given the partial pressures.

Kylie Lim 4G
Posts: 110
Joined: Sat Aug 17, 2019 12:15 am

### Re: using Kp vs Kc

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

Anna Heckler 2C
Posts: 102
Joined: Wed Sep 18, 2019 12:18 am

### Re: using Kp vs Kc

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.

lauraxie2e
Posts: 108
Joined: Fri Aug 09, 2019 12:17 am

### Re: using Kp vs Kc

You use Kp

Jaci Glassick 2G
Posts: 104
Joined: Sat Jul 20, 2019 12:16 am

### Re: using Kp vs Kc

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.

ayushibanerjee06
Posts: 177
Joined: Thu Jul 11, 2019 12:16 am
Been upvoted: 1 time

### Re: using Kp vs Kc

You can use both but as everyone else mentioned, make sure to pay attention if you are given atms or mols.

Vivianvelazquez_1J
Posts: 109
Joined: Thu Jul 11, 2019 12:17 am
Been upvoted: 1 time

### Re: using Kp vs Kc

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.

Nuoya Jiang
Posts: 99
Joined: Sat Sep 14, 2019 12:17 am

### Re: using Kp vs Kc

In fact, you can use both. Table 5G.2 shows an example of how Kc works for gas reactions.