Answer:
3.41
Step-by-step explanation:
(1.00atm) (2.00 L) /(27.0C) = (.500atm) (x)/ (-23.0C)
This is how you set it up because P1V1/T1 = P2V2/T2.
Then you can cross multiple, all units except Liters will cancel and you can solve for x and have your answer.