## 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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### 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
Joined: Sat Aug 17, 2019 12:18 am

### 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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### 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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### 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.