Why Does the Value of the Universal Gas Constant Change?

[roym6]

Clarification on "R" constant?

I'm pretty confused right now. The R constant, or universal gas constant has been troubling me. In one problem it is defined as .0821 L*atm/m*K. But soon after that it becomes 8.314 J/mol*K. Can somebody explain this concept to me? Thank you.

 

[dpsguy]

J is defined in terms of m³ and Pa. So convert L -> m³ and atm -> Pascals to get the new value of R.

 

[Borek]

Value depends on the units used, just like traveling at 62 mph and 100 km/h is the same thing. See the table on the right: http://en.wikipedia.org/wiki/Ideal_gas_constant