## T variable in pv=nrt [ENDORSED]

$PV=nRT$

Bryce Ramirez 1J
Posts: 120
Joined: Sat Aug 24, 2019 12:16 am

### T variable in pv=nrt

For the temperature in every calculation using the ideal gas formula, will it always be in Kelvin or will there be times where it is in Celcius? I know that the units have to cancel from the gas constant, but I'm not sure if there is any gas constant that requires celcius instead of Kelvin.

vpena_1I
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### Re: T variable in pv=nrt

All gas constants are in Kelvin, so unless you really wanted to convert these to Celsius, its easier to convert Celsius to kelvin from the get-go.

Zoya Mulji 1K
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### Re: T variable in pv=nrt

you should probably always keep it in Kelvin just to be safe because if it cancels out it won't matter anyways.

SMIYAZAKI_1B
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Joined: Sat Aug 24, 2019 12:15 am

### Re: T variable in pv=nrt

It is better to keep it in Kelvin just because of the unit of the gas constant, R, has Temperature in Kelvin. In order to cancel out the units, you really have to make sure that units match and if you really really need Celcius, make sure to change the unit after figuring the Kelvin.

Alfred Barrion 2H
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### Re: T variable in pv=nrt

For simplicity, it would be easier to use Kelvin, especially since Kelvin is used in the constants.

Frank He 4G
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### Re: T variable in pv=nrt

We should always work in kelvin just to be safe, so I'd convert to kelvin if needed and keep it that way. If the problem asks for a value using Celsius, then convert it back at the end.

Katie Kyan 2K
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### Re: T variable in pv=nrt

I think I would keep the units in Kelvin because this is usually what we work with and most likely the temperature will be given to you in Kelvin.

Alan Cornejo 1a
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### Re: T variable in pv=nrt

Using kelvin is most advisable as it is an easy conversion, and it allows for the matchup of all the right units for your equation.

KHowe_1D
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### Re: T variable in pv=nrt

Since Kelvin would be canceled out by the units of R, you should convert all temperatures to K.

Nawal Dandachi 1G
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Joined: Sat Sep 28, 2019 12:16 am

### Re: T variable in pv=nrt

You should convert temperature to kelvin because you are using R which uses Kelvin.

Gurmukhi Bevli 4G
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### Re: T variable in pv=nrt

I would keep it in Kelvin at all times, just to be safe.

My-Lan Le 1L
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### Re: T variable in pv=nrt

It should be in Kelvin so that the the units of T can match the units of R.

Jack_Pearce_2H
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Joined: Wed Sep 30, 2020 9:48 pm

### Re: T variable in pv=nrt

They're always supposed to be in Kelvin, not Celsius.

Karl Yost 1L
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Joined: Thu Dec 17, 2020 12:19 am

### Re: T variable in pv=nrt  [ENDORSED]

Conventionally, the gas constant units are all in Kelvin. Since we typically want the temperature units to cancel out when performing calculations (unless we're explicitly solving for temperature, T will also be in Kelvin to ensure that the temperature units from R and T do indeed cancel.

Posts: 98
Joined: Wed Sep 30, 2020 9:51 pm

### Re: T variable in pv=nrt

I would leave the temperature in Kelvin for its units because that is the correct unit when using ideal gas laws.

annabelchen2a
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Joined: Wed Sep 30, 2020 10:01 pm

### Re: T variable in pv=nrt

My thinking from high school chemistry was for temperature in the ideal gas law, you need to use a scale that starts at absolute zero - and the Kelvin scale does that.
If you were to use the Celsius scale and used a temperature equivalent of one below 273K, then you'd have a negative volume or pressure which just doesn't make sense. So I believe Kelvin is just the easiest scale/unit to use.

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### Re: T variable in pv=nrt

If you wanted to use Celsius, you would have to convert the gas constant (R) accordingly. I would recommend staying in Kelvin!

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### Re: T variable in pv=nrt

It's probably easier to convert from Celsius to Kelvin so that you only need to memorize one R constant rather than both R constants

jessicasilverstein1F
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### Re: T variable in pv=nrt

It will always be in Kelvin. Be sure to make sure this is the value you have.

Posts: 95
Joined: Wed Sep 30, 2020 9:35 pm

### Re: T variable in pv=nrt

Hi! The temperature should always be in Kelvin because all gas constants use Kelvin as their unit for temperature so it's just easier. :)

Rahul Sobti 1E
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### Re: T variable in pv=nrt

Temperature should always be in Kelvin because that is how all the other variables units will cancel out with. If you make it Celsius, you will have to change the units of the whole equation or of other units to compensate. I think people like to use Kelvin because it is only zero at absolute zero whereas Celsius is zero at a relatively normal temperature, so it makes calculations more accurate by using Kelvin.

Chudi Onyedika 3A
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### Re: T variable in pv=nrt

You should stick with Kelvin as the unit of temperature in this equation.

Sophia Spungin 2E
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### Re: T variable in pv=nrt

As people have mentioned, I would always use temperature in Kelvin as the alternative would be changing the units on the constants and pressure values. Its super simple to convert from Celsius to Kelvin if the temperature happens to be given in Celsius, all you have to do is take the temperature in Celsius and add 273.15 to convert to Kelvin.

Juliana Rosales 1H
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### Re: T variable in pv=nrt

I would say always to assume kelvin unless Celsius is specified.

Nick Saeedi 1I
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### Re: T variable in pv=nrt

I usually tend to keep it in Kelvin.

Joshua_Chan_3K
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### Re: T variable in pv=nrt

I don't think its possible for you to ever find a gas law with the units in Celsius because the unit conversion from Celsius to Kelvin is a addition and not multiplication. It just wouldn't be possible to factor that into the unit calculations.

DominicMalilay 1F
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### Re: T variable in pv=nrt

I personally never keep my units in celsius for the t variable as its just easier to remember!

Alejandro Gonzalez 2G
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Joined: Wed Sep 30, 2020 10:04 pm

### Re: T variable in pv=nrt

I think it's easier to keep the t units in Kelvin in the long run.

Jared Limqueco 3E
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### Re: T variable in pv=nrt

Most of the time it is in Kelvin.

Posts: 93
Joined: Wed Sep 30, 2020 9:38 pm

### Re: T variable in pv=nrt

When dealing with the ideal gas law, you must always use kelvin for temperature.

Brandon McClelland3L
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Joined: Wed Sep 30, 2020 9:31 pm

### Re: T variable in pv=nrt

You will probably always use Kelvin. The equation doesn't work unless the unit for temperature has absolute zero = 0.

Gustavo_Chavez_1K
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### Re: T variable in pv=nrt

Dr. Lavelle stated in lecture that we will almost always use Kelvin when working with temperature in equations.

reyvalui_3g
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Joined: Wed Sep 30, 2020 9:52 pm

### Re: T variable in pv=nrt

It will always be un Kelvin.

Tiao Tan 3C
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Joined: Wed Sep 30, 2020 9:59 pm

### Re: T variable in pv=nrt

T must always be in Kelvin. But if you are given in Celcius, you can convert it into Kelvin with the equation Kelvin = Celsius + 273.15.

Pranav Daggubati 3C
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Joined: Wed Sep 30, 2020 9:35 pm

### Re: T variable in pv=nrt

T is always in Kelvin because the gas constant r has a kelvin unit in it.

Tikva Cohen 1K
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### Re: T variable in pv=nrt

It has to be in Kelvin in order to cancel out the units, but if you're given something else you can just convert it.

MariaCassol1L
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Joined: Wed Nov 13, 2019 12:18 am

### Re: T variable in pv=nrt

It should always be in Kelvin if the problem gives you temperature units in Celsius you should convert it before plugging it in.

ShinwooKim_3E
Posts: 90
Joined: Wed Sep 30, 2020 10:00 pm

### Re: T variable in pv=nrt

Always keep the units in Kelvin so you don't accidently miscalculate.

Sameer Chowdhury 3C
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Joined: Wed Sep 30, 2020 9:41 pm

### Re: T variable in pv=nrt

For the T in pv=nrt, it should always stay in Kelvin.