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### Kelvin or Celsius?

Posted: Sun Feb 09, 2020 10:03 pm
when using PV=nRT is the temperature supposed to be celsius or kelvin?

### Re: Kelvin or Celsius?

Posted: Sun Feb 09, 2020 10:05 pm
I think you use Kelvin because the gas constant R always has Kelvin in the denominator so they cancel out!

### Re: Kelvin or Celsius?

Posted: Sun Feb 09, 2020 11:01 pm
Use Kelvin

### Re: Kelvin or Celsius?

Posted: Sun Feb 09, 2020 11:21 pm
Kelvin... The gas constant R is listed in Kelvin so Kelvin is used in equation.

### Re: Kelvin or Celsius?

Posted: Sun Feb 09, 2020 11:58 pm
Whenever it is T alone, you should use kelvin but when it is deltaT, you can use Celcius or kelvin.

### Re: Kelvin or Celsius?

Posted: Mon Feb 10, 2020 12:02 am
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

### Re: Kelvin or Celsius?

Posted: Mon Feb 10, 2020 12:07 am
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.

### Re: Kelvin or Celsius?

Posted: Sun Feb 16, 2020 9:10 pm
Kelvin. it only doesn't matter if we are talking about change. If it is a capital T then it must be Kelvin

### Re: Kelvin or Celsius?

Posted: Tue Feb 18, 2020 9:13 pm
You would use kelvin.

### Re: Kelvin or Celsius?

Posted: Tue Feb 18, 2020 9:20 pm
Kelvin, because the gas constant R is usually in terms of Kelvins.

### Re: Kelvin or Celsius?

Posted: Tue Feb 18, 2020 9:36 pm
temperature is always kelvin

### Re: Kelvin or Celsius?

Posted: Sun Feb 23, 2020 11:28 pm
Should use Kelvin so the units match the constant.

### Re: Kelvin or Celsius?

Posted: Sun Mar 01, 2020 8:57 pm
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

### Re: Kelvin or Celsius?

Posted: Sun Mar 01, 2020 8:58 pm
Temperature is always Kelvin in PV = nRT.

### Re: Kelvin or Celsius?

Posted: Sun Mar 01, 2020 8:58 pm
Kelvin because the ideal gas constant is in terms of Kelvin not celsius.

### Re: Kelvin or Celsius?

Posted: Sun Mar 01, 2020 9:28 pm
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.

### Re: Kelvin or Celsius?

Posted: Sun Mar 01, 2020 9:32 pm
Definitely use Kelvin

### Re: Kelvin or Celsius?

Posted: Sun Mar 01, 2020 9:38 pm
you must use Kelvin because of the units in the gas constant R

### Re: Kelvin or Celsius?

Posted: Sun Mar 01, 2020 11:46 pm
Use Kelvin, as the gas constant R includes it.

### Re: Kelvin or Celsius?

Posted: Mon Mar 02, 2020 8:03 am
kelvin, just make sure the units for R is the same

### Re: Kelvin or Celsius?

Posted: Mon Mar 02, 2020 8:51 am
You should use Kelvin because R uses Kelvin.

### Re: Kelvin or Celsius?

Posted: Mon Mar 02, 2020 9:07 am
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.

### Re: Kelvin or Celsius?

Posted: Mon Mar 02, 2020 10:12 am
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.

### Re: Kelvin or Celsius?

Posted: Sat Mar 07, 2020 12:20 am
The temperature should be in kelvin.

### Re: Kelvin or Celsius?

Posted: Sat Mar 07, 2020 12:26 am
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.

### Re: Kelvin or Celsius?

Posted: Sat Mar 07, 2020 11:01 am
You use Kelvin since the units of R include Kelvin.

### Re: Kelvin or Celsius?

Posted: Sat Mar 07, 2020 10:42 pm
Temperature is always in Kelvin, not Celsius.

### Re: Kelvin or Celsius?

Posted: Sun Mar 08, 2020 6:40 pm
kelvin

### Re: Kelvin or Celsius?

Posted: Sun Mar 08, 2020 10:02 pm
yup, as mentioned above, you would use Kelvin.

### Re: Kelvin or Celsius?

Posted: Mon Mar 09, 2020 1:50 pm
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.

### Re: Kelvin or Celsius?

Posted: Mon Mar 09, 2020 1:54 pm
You should use Kelvin since it matches with the gas constant R to cancel out.

### Re: Kelvin or Celsius?

Posted: Mon Mar 09, 2020 2:10 pm
You use Kelvin because you must match the units within the R (gas constant) which uses kelvin.

### Re: Kelvin or Celsius?

Posted: Mon Mar 09, 2020 2:18 pm
kelvin because the gas constant is always in terms of kelvin.

### Re: Kelvin or Celsius?

Posted: Wed Mar 11, 2020 10:24 pm
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).

### Re: Kelvin or Celsius?

Posted: Wed Mar 11, 2020 10:25 pm
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)

### Re: Kelvin or Celsius?

Posted: Thu Mar 12, 2020 11:06 am
Kelvin = Celsius + 273.15; the two are on the same scale so converting between the two isn't too tricky.

### Re: Kelvin or Celsius?

Posted: Thu Mar 12, 2020 11:07 am
kelvin because the gas constant R is in K. sometimes it is in C and in that case u would use C

### Re: Kelvin or Celsius?

Posted: Thu Mar 12, 2020 11:23 am
Kelvin, just make sure all the units cancel

### Re: Kelvin or Celsius?

Posted: Thu Mar 12, 2020 11:45 am
Kelvin

### Re: Kelvin or Celsius?

Posted: Sun Mar 15, 2020 8:06 am
Use kelvin and make sure your units match up.

### Re: Kelvin or Celsius?

Posted: Sun Mar 15, 2020 12:50 pm
Kelvin

### Re: Kelvin or Celsius?

Posted: Sun Mar 15, 2020 1:22 pm
kelvin

### Re: Kelvin or Celsius?

Posted: Mon Mar 16, 2020 6:10 pm
Kelvin is always the unit for such equations.

### Re: Kelvin or Celsius?

Posted: Mon Mar 16, 2020 7:12 pm
It's always in Kelvin because the R constant uses units of Kelvin

### Re: Kelvin or Celsius?

Posted: Tue Mar 17, 2020 12:27 pm
kelvin so it cancels out with the units of R

### Re: Kelvin or Celsius?

Posted: Tue Mar 17, 2020 8:42 pm
You use Kelvin, because the unit for R in this equation has K in it.

### Re: Kelvin or Celsius?

Posted: Tue Mar 17, 2020 9:31 pm
Use Kelvin since this is the SI unit for temperature.

### Re: Kelvin or Celsius?

Posted: Tue Mar 17, 2020 10:19 pm
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.