## Kelvin or Celsius?

Veronica Lu 2H
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### Kelvin or Celsius?

when using PV=nRT is the temperature supposed to be celsius or kelvin?

KSong_1J
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### Re: Kelvin or Celsius?

I think you use Kelvin because the gas constant R always has Kelvin in the denominator so they cancel out!

Timmy Nguyen Dis 1I
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### Re: Kelvin or Celsius?

Use Kelvin

Shrayes Raman
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### Re: Kelvin or Celsius?

Kelvin... The gas constant R is listed in Kelvin so Kelvin is used in equation.

Alexis Robles 2k
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### Re: Kelvin or Celsius?

Whenever it is T alone, you should use kelvin but when it is deltaT, you can use Celcius or kelvin.

Venus_Hagan 2L
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### Re: Kelvin or Celsius?

for the ideal gas equation use Kelvin but if you ever need the change in temperature it doesn't matter because both are scaled the same way

gconcha
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### Re: Kelvin or Celsius?

Kelvins are always used when applying the ideal gas law $PV=nRT$

The reason this is done is because Kelvins are more mathematically accurate in terms of chemically applying the excited state of the molecules in a gas to your calculations. zero K is the same as zero energy in the molecules, and is therefore the same as zero movement of the molecules. This is more mathematically correct than -273.15oC
If you really want, I'm sure you could look up values for the Ideal Gas Constant $R$, but most are given in K because they're better for representing how the energy of the molecules affects the context.

Rosa Munoz 2E
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### Re: Kelvin or Celsius?

Kelvin. it only doesn't matter if we are talking about change. If it is a capital T then it must be Kelvin

Juana Abana 1G
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### Re: Kelvin or Celsius?

You would use kelvin.

Aarushi Solanki 4F
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### Re: Kelvin or Celsius?

Kelvin, because the gas constant R is usually in terms of Kelvins.

205405339
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### Re: Kelvin or Celsius?

temperature is always kelvin

Jesse Anderson-Ramirez 3I
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### Re: Kelvin or Celsius?

Should use Kelvin so the units match the constant.

Anish Natarajan 4G
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### Re: Kelvin or Celsius?

Technically it's all dependent on the value of R that you use, but in most cases you'll be given a value that incorporates Kelvin rather than Celsius

Orrin Zhong 4G
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### Re: Kelvin or Celsius?

Temperature is always Kelvin in PV = nRT.

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

### Re: Kelvin or Celsius?

Kelvin because the ideal gas constant is in terms of Kelvin not celsius.

CalvinTNguyen2D
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### Re: Kelvin or Celsius?

You will almost always be using Kelvin in equations and calculations; in terms of the gas constant, it is measured in Kelvin rather than Celsius.

Celine 1F
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### Re: Kelvin or Celsius?

Definitely use Kelvin

105311039
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### Re: Kelvin or Celsius?

you must use Kelvin because of the units in the gas constant R

Sean Tran 2K
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### Re: Kelvin or Celsius?

Use Kelvin, as the gas constant R includes it.

605395381
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### Re: Kelvin or Celsius?

kelvin, just make sure the units for R is the same

AveryAgosto
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### Re: Kelvin or Celsius?

You should use Kelvin because R uses Kelvin.

Esha Chawla 2E
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### Re: Kelvin or Celsius?

Veronica Lu 2H wrote:when using PV=nRT is the temperature supposed to be celsius or kelvin?

The units for R are L*atm/mol*K. Based on this information, we can determine that R should be in Kelvin.

In general, most chemical reactions use temperature in Kelvin.

Aarushi Solanki 4F
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Joined: Sat Jul 20, 2019 12:17 am

### Re: Kelvin or Celsius?

It's supposed to be in Kelvin. Generally, we use Kelvin, but it is okay to use Celsius in equations involving the "change of T" since the scaling is the same for Kelvin and Celsius.

Gurmukhi Bevli 4G
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### Re: Kelvin or Celsius?

The temperature should be in kelvin.

Brandi 2C
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### Re: Kelvin or Celsius?

Since the STP (standard temperature and pressure) and R constant are in units of Kelvin, you should be using Kelvin for your calculations. If the problem does ask for the answer in units of Celsius, just do the calculations in Kelvin and then convert to Celsius after completing the calculations so you don't mess up unit calculations.

Posts: 103
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### Re: Kelvin or Celsius?

You use Kelvin since the units of R include Kelvin.

Yailin Romo 4G
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### Re: Kelvin or Celsius?

Temperature is always in Kelvin, not Celsius.

Owen-Koetters-4I
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### Re: Kelvin or Celsius?

kelvin

Areli C 1L
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### Re: Kelvin or Celsius?

yup, as mentioned above, you would use Kelvin.

Justin Quan 4I
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### Re: Kelvin or Celsius?

Veronica Lu 2H wrote:when using PV=nRT is the temperature supposed to be celsius or kelvin?

To add on, you use kelvin especially since the constant R is in kelvin, not celsius. However, if you use PV=nR∆T, the you may use either celsius or kelvin since the change in temperature would be the same.

Alfred Barrion 2H
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### Re: Kelvin or Celsius?

You should use Kelvin since it matches with the gas constant R to cancel out.

105335337
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### Re: Kelvin or Celsius?

You use Kelvin because you must match the units within the R (gas constant) which uses kelvin.

pmokh14B
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### Re: Kelvin or Celsius?

kelvin because the gas constant is always in terms of kelvin.

William Chan 1D
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### Re: Kelvin or Celsius?

Kelvin. If the reaction happened at below 0°C, then the subsequent equation would be negative, having some weird consequences (i.e., negative pressure, negative volume).

Bryan Chen 1H
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Joined: Mon Jun 17, 2019 7:24 am

### Re: Kelvin or Celsius?

it depends on the unit of the gas constant. if its .08206 Latm/Kmol then use Kelvin, but another gas constant COULD have its units in celcius for whatever reason and then you should use celcius (but it probably will never ever come up in real life or a problem)

Leonardo Le Merle 1D
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Joined: Wed Feb 27, 2019 12:16 am

### Re: Kelvin or Celsius?

Kelvin = Celsius + 273.15; the two are on the same scale so converting between the two isn't too tricky.

Tanmay Singhal 1H
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### Re: Kelvin or Celsius?

kelvin because the gas constant R is in K. sometimes it is in C and in that case u would use C

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### Re: Kelvin or Celsius?

Kelvin, just make sure all the units cancel

Rodrigo2J
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### Re: Kelvin or Celsius?

Kelvin

Alan Cornejo 1a
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### Re: Kelvin or Celsius?

Use kelvin and make sure your units match up.

Elizabeth Harty 1A
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### Re: Kelvin or Celsius?

Kelvin

Anushka Chauhan2B
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### Re: Kelvin or Celsius?

kelvin

Ayushi2011
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### Re: Kelvin or Celsius?

Kelvin is always the unit for such equations.

Charlene Datu 2E
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### Re: Kelvin or Celsius?

It's always in Kelvin because the R constant uses units of Kelvin

Posts: 49
Joined: Thu Jul 25, 2019 12:16 am

### Re: Kelvin or Celsius?

kelvin so it cancels out with the units of R

SVajragiri_1C
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### Re: Kelvin or Celsius?

You use Kelvin, because the unit for R in this equation has K in it.

EllieSchmidtke_4I
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### Re: Kelvin or Celsius?

Use Kelvin since this is the SI unit for temperature.

Bella Townsend
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### Re: Kelvin or Celsius?

Typically, you only ever use celsius is there is a change in temperature (delta T) because then the units don't matter. The difference will be the same.

Susan Chamling 1F
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### Re: Kelvin or Celsius?

Use Kelvin because it will cancel with the units for R.

Ariel Guan 1H
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### Re: Kelvin or Celsius?

Kelvin because SI units

Katie Phan 1K
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### Re: Kelvin or Celsius?

Kelvin

Nick P 3D
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### Re: Kelvin or Celsius?

Using PV=nRT you always use kelvin

David Jen 1J
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### Re: Kelvin or Celsius?

use kelvin.

Will Skinner
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### Re: Kelvin or Celsius?

It is always kelvin.

Rajshree 1F
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### Re: Kelvin or Celsius?

kelvin i am pretty sure

Emma Strassner 1J
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### Re: Kelvin or Celsius?

Hi, you would use Kelvin and make sure to convert from other units like Celsius.

Mursall M 2A
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### Re: Kelvin or Celsius?

You should be using Kelvin so it can cancel with the units for the R constant.

Keeryth Sandhu 1H
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### Re: Kelvin or Celsius?

I'm pretty sure Kelvin

Ismar Zamora
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### Re: Kelvin or Celsius?

Kelvin

Maya Johnson 2a
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### Re: Kelvin or Celsius?

Use Kelvin.

Gwirnowski 3B
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### Re: Kelvin or Celsius?

Kelvin is always used with the ideal gas law as the units need to cancel out in the end.

Michelle Nguyen 3F
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### Re: Kelvin or Celsius?

Kelvin is the units used in the ideal gas law!

Katelyn_Ortega_1D
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### Re: Kelvin or Celsius?

You should be using kelvin, not celsius.

Taylor Newville 1C
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### Re: Kelvin or Celsius?

You would use Kelvin. If you are ever unsure about what units to use, look at the units of the equation's constant to see what needs to be canceled out. For the Ideal Gas Law, the gas constant R= 8.314 J/mol·K, so the temperature needs to be in Kelvins too.

Crystal Pan 2G
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### Re: Kelvin or Celsius?

That equation requires the usage of Kelvins.

Darlene Lien 3E
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### Re: Kelvin or Celsius?

You would use Kelvin. If you look at the constants and equations sheet, the units for the rate are in Kelvin. Hope this helps!

Joshua Chung 2D
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### Re: Kelvin or Celsius?

Default to Kelvin here.

Lauren Strickland 1B
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### Re: Kelvin or Celsius?

It would be kelvin.

Rayna Irving 2C
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### Re: Kelvin or Celsius?

Kelvin because in this case the rate, R, is a value that corresponds with the unit Kelvin.

Jack Kettering 3D
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### Re: Kelvin or Celsius?

Always use kelvin as this is the SI unit for temperature

Bai Rong Lin 2K
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### Re: Kelvin or Celsius?

I believe we are supposed to use the kelvin when solving.

Jiapeng Han 1C
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### Re: Kelvin or Celsius?

Temperature is in Kelvin!

Brandon Le 3C
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### Re: Kelvin or Celsius?

Using Kelvin is more beneficial because it is a more accurate measurement of the movement of molecules that determine the temperature of a system.

LeanneBagood_2F
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### Re: Kelvin or Celsius?

as everyone has already said, temperature is always in Kelvin. this is not limited to just the PV = nRT equation as we will see throughout the remaining weeks

Sejal Parsi 3K
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### Re: Kelvin or Celsius?

I believe you would use Kelvin as the constant R uses that unit as well.

Joshua Swift
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### Re: Kelvin or Celsius?

You would use Kelvin, but if you are calculating $\Delta$T, kelvin or celsius works.

Violet Kwan 3H
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### Re: Kelvin or Celsius?

Kelvin is the SI unit for temperature, so I believe you would use that. Also, the conversion is just adding 273.15 to Celsius, so better just to be safe and convert to Kelvin.

Ethan Goode 2H
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### Re: Kelvin or Celsius?

I believe you should be using Kelvin when looking at PV=nRT

Edison Tham 3D
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### Re: Kelvin or Celsius?

Typically, since the gas constant R is given in Kelvin, we would use temperature in Kelvin when looking at the equation PV=nRT.

Will Skinner
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### Re: Kelvin or Celsius?

It should be Kelvin

Chinyere Okeke 2J
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### Re: Kelvin or Celsius?

In this class and most Thermodynamic classes in the US, we are doing our calculations in Kelvin, this is because a lot of values/constants have Kelvin in their units not Celsius. The only time you wouldn't need to change the degrees is when you are doing change in temperature since change in 1 K = change in 1 degree-Celsius.

Claudia_Danysh_2B
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### Re: Kelvin or Celsius?

The temperature is supposed to be in Kelvin!!

Rose_Malki_3G
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### Re: Kelvin or Celsius?

It is supposed to be in kelvin(:

Charmaine Ng 2D
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### Re: Kelvin or Celsius?

You use Kelvin so that the units cancel out! :))

Jordan Tatang 3L
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### Re: Kelvin or Celsius?

Kelvin

jasmineculilap_3F
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### Re: Kelvin or Celsius?

kelvin bc R is in kelvin

Ximeng Guo 2K
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Kelvin(K)
K=℃+273