When do you use 0.08206 l atm versus 8.345 l atm? Can you tell me how you decipher when to use one or the other generally?
You are referring to the units of the gas constant, R.
R may be expressed in a number of different ways. You choose which one you wish to use depending on the units in the rest of the problem.
These are your choices:
This solution is provided in 168 words. It discusses the different version of the gas constant and in which situations each can be best applied to.