Which gas law do I use for this problem? Or do I use a gas law? Help please.?

Im stuck on this problem. A 100.0mL flask contains 400 g of N2 at 0�C. What is the pressure in atm? What is the pressure in torr? What is the pressure in psi? Im not sure how to do this problem. Am I supposed to use one of the gas laws? Do I convert mL to L and the 400g to moles? I dont want answers I just want to know how to set up the problem. Thanks!