When to use this equation

$PV=nRT$

Tai Metzger 3K
Posts: 103
Joined: Sat Aug 24, 2019 12:17 am

When to use this equation

Hi, I was wondering when it is useful to use PV=nRT. Thanks!

Alex Tchekanov Dis 2k
Posts: 118
Joined: Sat Aug 24, 2019 12:16 am

Re: When to use this equation

This equation has many uses, however, the one that Lavelle talked about in class is when you want to convert pressure to concentration as the following:
PV=nRT
P=(n/V)RT
P=concRT
Conc=P/RT

Kishan Shah 2G
Posts: 132
Joined: Thu Jul 11, 2019 12:15 am

Re: When to use this equation

In the context of equilibrium, you use this equation to convert from pressure to concentration. So if you want to calculated K(p) and you are given concentration values, you can use PV=nRT to convert to partial pressure values for that reactant or product. The same applies for converting from pressure to concentration.

AniP_2D
Posts: 95
Joined: Sat Aug 17, 2019 12:17 am

Re: When to use this equation

An example of when to use this function is if you are given pressure and need to find concentration. You can also use it to find the pressure if you are given concentration.

anjali41
Posts: 109
Joined: Fri Aug 09, 2019 12:15 am

Re: When to use this equation

You would use this equation to convert between partial pressure and concentration. If you were asked specifically for Kp or Kc and given the opposite units, you would use this equation.

Jainam Shah 4I
Posts: 130
Joined: Fri Aug 30, 2019 12:16 am

Re: When to use this equation

If you are given concentrations and asked to find Kp you can rearrange PV=nRT to solve for the partial pressures of the reactants and products. Conversely, if you were given partial pressures and asked to find Kc you could use the equation to convert the partial pressures into concentrations.

Naneeta Desar 1K
Posts: 106
Joined: Fri Aug 09, 2019 12:15 am

Re: When to use this equation

This equation is the ideal gas equation and should be used when you want to convert the concentration to pressure or vice versa.

805422680
Posts: 103
Joined: Sat Sep 14, 2019 12:16 am

Re: When to use this equation

PV= nRT is used for ideal gases only. if concentrations and Kp are given, this equation can be used to calculate the partial pressure of products and reactants and vice versa, if partial pressures are given, concentrations can be calculated using this method

Posts: 111
Joined: Thu Jul 25, 2019 12:17 am

Re: When to use this equation

This equation is super versatile. If you know a few variables and you are trying to figure out how to represent ideal gases differently, then, you can just rearrange the equation. For example, if you have the pressure of a gas, but want to know what the concentration of the gas is you just need to rearrange it to say: PV = nRT to P/RT = n/V.
n/V is concentration by the way (mols/volume)

This is really useful if you are trying to go from Kp to Kc.

205150314
Posts: 106
Joined: Wed Feb 20, 2019 12:16 am

Re: When to use this equation

I think you use PV=nRT when you're trying to switch between concentration and pressure of when trying to calculate the partial pressures.

CameronDis2K
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Joined: Wed Feb 20, 2019 12:18 am

Re: When to use this equation

One use is when a compound or reaction is not in the STP state (standard 1atm, 25C), and you need to find a certain value to plug into a stoichiometric equation. More for specialized cases...

Nick Lewis 4F
Posts: 111
Joined: Wed Sep 18, 2019 12:18 am

Re: When to use this equation

PV= nRT is an overarching equation that can be manipulated to define a lot of different laws within chemistry, but I think the main thing to notice is the effect temperature has on pressure and volume, and the inversely proportional relationship between p and v

SarahCoufal_1k
Posts: 102
Joined: Thu Jul 25, 2019 12:17 am

Re: When to use this equation

it's used to convert between pressure and concentration. When you are finding K for gasses that could. be in either pressure or concentration. You manipulate the equation to get a. simpler conversion. It starts as PV=nRT. then divide by V for P=(n/V)RT. And n/v is moles/Liter which is the definition of concentration. So, Pressure=concentration*RT which is then
Concentration=Pressure/RT

Trent Yamamoto 2J
Posts: 111
Joined: Sat Aug 17, 2019 12:18 am

Re: When to use this equation

PV=nRT is used to convert from a pressure of a gas back into a concentration

Ruth Glauber 1C
Posts: 100
Joined: Wed Sep 18, 2019 12:20 am

Re: When to use this equation

Are there any conditions where you can't use it? Like that could be a trick question?