When to Use PV=nRT


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Sophia Diaz - Dis 1B
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When to Use PV=nRT

Postby Sophia Diaz - Dis 1B » Sun Jan 13, 2019 11:50 am

I don't really understand when we have to use this equation. When we are solving for Kp don't we use solve with [Products]/{Reactants]? When are we supposed to use the entire equation of PV=nRT?

WilliamNguyen_4L
Posts: 65
Joined: Fri Sep 28, 2018 12:28 am

Re: When to Use PV=nRT

Postby WilliamNguyen_4L » Sun Jan 13, 2019 11:53 am

You use PV=nRT when the problem gives you have to convert between partial pressure and concentration. If a problem gave you concentrations and made you solve for Kp then you would rearrange the equation into
P=(V/n)RT. Since V/n represents concentration you would then just plug in the concentration for V/n to solve for the partial pressure and then you can calculate Kp.

Abby-Hile-1F
Posts: 46
Joined: Fri Sep 28, 2018 12:16 am

Re: When to Use PV=nRT

Postby Abby-Hile-1F » Sun Jan 13, 2019 3:53 pm

PV=nRT can be used to relate Kc and Kp since you can use it to convert between partial pressure and concentration.

Hannah Pham 1D
Posts: 62
Joined: Fri Sep 28, 2018 12:19 am

Re: When to Use PV=nRT

Postby Hannah Pham 1D » Sun Jan 13, 2019 3:56 pm

For this class, I think we just need to use this equation when we convert from concentration to partial pressure, so when you are solving for Kc, you need concentrations and when you are solving for Kp, you need partial pressures.

505095793
Posts: 61
Joined: Fri Sep 28, 2018 12:25 am

Re: When to Use PV=nRT

Postby 505095793 » Sun Jan 13, 2019 4:11 pm

The main use of the ideal gas law, PV=nRT, for us is to convert between Kc and Kp (concentration and partial pressure). You can think of the ideal gas equation as Kp=Kc(RT)^(n). In this case n=(c+d)-(a+b) according to the reaction form aA+bB=cC+dD.

204929947
Posts: 76
Joined: Fri Apr 06, 2018 11:03 am

Re: When to Use PV=nRT

Postby 204929947 » Sun Jan 13, 2019 9:27 pm

what does PV=nRT stand for???

lizettelopez1F
Posts: 29
Joined: Fri Sep 28, 2018 12:19 am

Re: When to Use PV=nRT

Postby lizettelopez1F » Sun Jan 13, 2019 9:39 pm

204929947 wrote:what does PV=nRT stand for???

It represents the ideal gas law.
P= Pressure, V=volume, n= number of moles, R= constant, T= Temperature

Tessa Lawler 1A
Posts: 57
Joined: Fri Sep 28, 2018 12:18 am

Re: When to Use PV=nRT

Postby Tessa Lawler 1A » Sun Jan 13, 2019 10:35 pm

Dr. Lavelle also did a practice problem in lecture on Friday showing when we would use PV=nRT, using V and n to represent concentration.

Brian Chang 2H
Posts: 65
Joined: Fri Sep 28, 2018 12:17 am

Re: When to Use PV=nRT

Postby Brian Chang 2H » Sun Jan 13, 2019 10:36 pm

PV=nRT is used to convert between concentration and partial pressure (for your Kc and Kp calculations).

The symbols represent P= Pressure, V=Volume, n= Number of Moles, R= Gas Constant, T= Temperature


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