## R Constant

$PV=nRT$

Alexis Robles 2k
Posts: 100
Joined: Wed Sep 18, 2019 12:18 am

### R Constant

What is the R constant in PV=nRT, I keep hearing there are different R constant and I am confused about that?

Donavin Collins 1F
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Joined: Sat Sep 14, 2019 12:16 am

### Re: R Constant

The gas constant, R, is 8.314 J/mol·K I believe.

Nicholas Chin 1G
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Joined: Thu Jul 11, 2019 12:17 am

### Re: R Constant

The R constant is the universal gas constant, and the reason there are different values for it is because the units can vary, from atmospheres to barrs.

DHavo_1E
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Joined: Sat Aug 17, 2019 12:17 am

### Re: R Constant

Alexis Robles 2k wrote:What is the R constant in PV=nRT, I keep hearing there are different R constant and I am confused about that?

Hello,

For the Ideal Gas Law (PV=nRT), R= 8.314J/molK, which is the universal gas constant. I believe there is also differing R constants depending on units used. I found the section "The Gas Constant (R)" on this website to be helpful!

https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/States_of_Matter/Properties_of_Gases/Gas_Laws/The_Ideal_Gas_Law

Jesalynne 2F
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Joined: Wed Sep 18, 2019 12:18 am

### Re: R Constant

The R constant will be provided on the "Constants and Formulas" worksheet which can be found on the 14B class website and will be provided on tests and midterms, so we will not have to remember it. The constant can change depending on what units it is in, but different unit forms are also provided on the formula sheet.

cassidysong 1K
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Joined: Fri Aug 30, 2019 12:15 am

### Re: R Constant

There are different R constants that have different units so you just pick the R constant that has units matching the other parts (i.e. atm or bar)

Jasmine Vallarta 2L
Posts: 102
Joined: Sat Aug 17, 2019 12:18 am

### Re: R Constant

The R constant differs depending on what units are used for pressure so we don't have to manually convert it

205389184
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Joined: Sat Sep 07, 2019 12:18 am

### Re: R Constant

There are different values for the constant R but that is only because it depends on the units that are being used, but they will be provided on the equation sheet that is given on the tests.

Chris Charton 1B
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Joined: Mon Jun 17, 2019 7:23 am

### Re: R Constant

R is the gas constant. It has different values depending on what units you are using.

Anish Natarajan 4G
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Joined: Thu Jul 25, 2019 12:16 am

### Re: R Constant

There are different values for R depending on the units that you are using in your calculations

AronCainBayot2K
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Joined: Fri Aug 30, 2019 12:17 am

### Re: R Constant

R constants are given and should be applied based on the units given in the problem. Pressure is the unit to look for as it determines which R constant to plug ig to PV = nRT

Anna Chen 1K
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Joined: Thu Jul 25, 2019 12:18 am

### Re: R Constant

The R constant is the gas constant. Its value is determined by the units in the specific problem.

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

### Re: R Constant

The R depends on what other units you are working with in your PV = nRT calculation.

Mandeep Garcha 2H
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Joined: Sat Aug 24, 2019 12:17 am

### Re: R Constant

The R constant is given on the sheet of constants and equations for the test, so you will not need to memorize it( but familiarize yourself with it).

Rosa Munoz 2E
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Joined: Wed Sep 18, 2019 12:21 am

### Re: R Constant

Look at the units to decide which one to use

Donna Nguyen 2L
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

### Re: R Constant

In many of our examples and homework problems, the R constant is 8.314 J/mol·K, but if you look at Dr. Lavelle's constants and equations sheet, R is the gas constant and actually has different values. The R value you use depends on the units that are given in the problem.

alex_4l
Posts: 109
Joined: Thu Sep 26, 2019 12:18 am

### Re: R Constant

8.314 J/mol·K is the most common used form for the R gas constant, but there are other types of numbers given for it depending on the units. I would suggest memorizing this number just in case the formula sheet has a different value on it since this is the most common used form of it used in our problems

WGaines_2E
Posts: 47
Joined: Mon Nov 18, 2019 12:18 am

### Re: R Constant

when using pv=nrt r is usually 8.314 J/molK but its gonna be given on the exam

CameronDis2K
Posts: 51
Joined: Wed Feb 20, 2019 12:18 am

### Re: R Constant

Correct, there are 3 different R values depending on the units that are presented to you, such as atm or torr. But they all are equivalent to each other (even though their units are somewhat different(.