Page 1 of 1
Posted: Sun Jan 13, 2019 8:33 pm
Hello, I am confused by what units we are to use when using the Pv=nRT equation, specifically in regards to R. There are various units you can have it in. However, it is unclear to me which ones are the correct ones when regarding to concentration.
Posted: Sun Jan 13, 2019 8:50 pm
R= .0821 (liters x atm)/(moles x kelvin)
Pressure is usually given in atm, so the units of R would be the unit mentioned above. However, if pressure is given in another unit, the unit of R also changes to correspond to the unit of pressure that is given.
Posted: Sun Jan 13, 2019 9:55 pm
R = 0.0821 atm x L / mol x K
Posted: Sun Jan 13, 2019 10:02 pm
(P)ressure is in atm (atmospheric)
(N) is moles
(V) is liters
(T) is kelvins
(R) is a constant ".0821" liters x atm/moles x kelvin
Posted: Mon Jan 14, 2019 12:20 am
From my perspective, I do not think that you need to know much about the definition of R or memorize the value of R. They will be given in the tests. However, one thing you need to know is how to apply different values and units under different circumstances. It all depends on the settings of the questions.
Hope this helps!
Re: R [ENDORSED]
Posted: Mon Jan 14, 2019 3:11 pm
I also asked my TA about this question, and he said that R is a constant, so we should not have to worry about remembering it like how we are given constants on the constant wkst.