Page 1 of 1

Gas Constant

Posted: Mon Nov 09, 2015 12:32 am
by Chu 3J
I noticed that there were two gas constants, R=8.314 JxK^-1 x mol^-1 and R=.0821 Lxatm/molxK
which types of problems would require the first one and which types of problems would require the second constant?

Re: Gas Constant

Posted: Mon Nov 09, 2015 12:39 am
by Chem_Mod
They are interchangeable. Usually you would use the first one when discussing thermodynamics in Chemistry 14B while the second one you will see frequently when dealing with ideal gases. In any case, the best constant to use is the one that allows you to relate your given quantities to what you want to find i.e. they cancel the units for measurements that you know. For example, if I have a pressure or volume, using the second constant makes calculations much easier, and for the most part you will be using it for this course.