The air in a dry, sealed 2L soda bottle has a pressure of 0.998 atm at sea level at a temperature of 34C. what will be it's pressure, if it is brought to higher altitude where the temperature is only 23C?

Answer 1

(P1V1)/T1 = (P2V2)/T2.
Remember T is in Kelvin.
You can cross out V1 and V2 since those are the same and don't change. Or you can leave them (at 2L) and calculate new pressure.

Answer 2

0.99atm