## Gas constant R

$PV=nRT$

Jenny Chau 1I
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### Gas constant R

How would we determine what the gas constant R is? Is it something that would have to be given or is it something that we might be expected to find?

Evie Li_1H
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### Re: Gas constant R

I think they mean it as the Gas Constant. It's on the constants and equations sheets where R Constant = 8.3144598 J/mol·K (not to be confused with Rydberg's Constant)

Joshua Swift
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### Re: Gas constant R

R is the universal gas constant and it = 8.3144598 J/mol·K

Morgan Gee 3B
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### Re: Gas constant R

All constants are given and on the equation/formula sheet that Professor Lavelle allows us to use. Just be careful to use the right constant based on the unit of the pressure. There are different constants depending on if the pressure is measured in bars, atm, etc.

Ryan Laureano 3I
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### Re: Gas constant R

Any constants in this class will be provided on the constants and equations sheet. Dr. Lavelle doesn't expect us to remember these but rather how to apply them. As for your question, R is a constant that is given.

Samudrala_Vaishnavi 3A
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### Re: Gas constant R

The constant of R is the ideal gas constant and you don't need to memorize anything regarding constants considering that they are all on the equations sheet. In terms of using the constant, the units tend to shift on whether you have the molar concentration (L*mol-1*K-1*atm)of something or you have the partial pressure of something (mol*L*atm/bar-1*K-1).

Ariel Guan 1H
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### Re: Gas constant R

The gas constant R is given on equation sheets!

Brianna Chen 3F
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### Re: Gas constant R

There are varying values for the constant R based on which unit you choose for partial pressure. However, since we calculate partial pressure in bar or atm most of the time, you would either use 8.20574x10^-2 (for atm) or 8.31446x10^-2 (for bar).

Uyenvy Nguyen 1D
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### Re: Gas constant R

it would be on the constant sheet :-)

Jason_John_2F
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### Re: Gas constant R

gas constant is given on the equation sheet as 8.3145 J mol^-1K^-1

Will Skinner
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### Re: Gas constant R

R is a constant, so it is given to us.

Jaclyn Schwartz 1I
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### Re: Gas constant R

The gas constant is a constant. So any time a constant is mentioned it means it will always be the same specific number. An similar example is pi; it is always 3.14. So the gas constant is always equals 8.3144598 J/mol·K.

SamayaJoshi1A
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### Re: Gas constant R

Why is the gas constant a constant? To me that part is a bit confusing because I would have thought the gas constant differs for each gas.

SamayaJoshi1A
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### Re: Gas constant R

Why is the gas constant a constant? To me that part is a bit confusing because I would have thought the gas constant differs for each gas.

sabrina ghalambor 2J
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Joined: Wed Sep 30, 2020 9:35 pm

### Re: Gas constant R

SamayaJoshi1A wrote:Why is the gas constant a constant? To me that part is a bit confusing because I would have thought the gas constant differs for each gas.

my understanding is that the gas constant has more to do with the state of the matter rather than its content if that makes sense? like it doesn't matter if its O2 or CO2 gas, but they both behave as gases and thats how the constant was found and why it can be universal.

Susan Chamling 1F
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### Re: Gas constant R

The gas constant R is universal and is provided to us on the equations sheet.

Caelin Brenninkmeijer 1G
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### Re: Gas constant R

The constant is universal, so the value will always remain consistent, equaling 8.3144598 J/mol·K.

Griffin G
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### Re: Gas constant R

R is the universal gas constant. It will be given on exams as a part of the constants and equations sheet. Lavelle doesn't expect us to memorize it.

emwoodc
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Joined: Fri Aug 09, 2019 12:16 am

### Re: Gas constant R

The Gas constant R is always given on the equations sheet and is constant so dw about memorizing it.

Devan Nathu - 2H
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### Re: Gas constant R

Where does the value for the gas constant come from? I understand that the value equals 8.3144598 J/mol·K, however how was this value calculated?

Posts: 93
Joined: Wed Sep 30, 2020 9:51 pm

### Re: Gas constant R

R is a constant, which would either be given to us on the equation sheet, or we'd have to know it. R= 8.3145

Jason Knight - 1F
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### Re: Gas constant R

The gas constant is on the equation sheet that we are allowed to use for the exams.

Muskaan Abdul-Sattar
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### Re: Gas constant R

R is a constant that is = 8.3144598 J/mol·K

Fiona Huang 3C
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### Re: Gas constant R

Devan Nathu - 2H wrote:Where does the value for the gas constant come from? I understand that the value equals 8.3144598 J/mol·K, however how was this value calculated?

Avogadro's Law says that at STP (which is 1.00 atm and 0 degreesC), 1.00 mole of a gas takes up 22.4 L. If you rearrange the ideal gas law PV=nRT, you get R=PV/nT. Assuming we are at STP, R= (1.00atm)(22.4L)/(1.00mole)(273K) = 0.0821. For the other values of R, you can calculate it using the conversion factors (1 atm=101.3 kPa=760. mmHg) If you convert the units, the R value would be 8.3144598 J/mol·K.

Gicelle Rubin 1E
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### Re: Gas constant R

As many before me have said, it is a constant :)
R = 8.3144598 J/mol·K

Julianna Shimabukuro 1D
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### Re: Gas constant R

As others have stated, R is a gas constant (R = 8.3144598 J/mol·K ), and it will be provided on the equations sheet as it was for chemistry 14A.

Chudi Onyedika 3A
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### Re: Gas constant R

You must choose the appropriate R value by looking at the units. Each R value is provided on the equations sheet.