Answer: P = 1.37 atm
Explanation: For this problem we will use the Gay Lussac Law which is P1/T1 = P2/T2 then derive for P2 which is the outside pressure. Also remember to convert the units of temperature from °C to Kelvin.
T1 = 20°C + 273 = 293 K
T2 = -5°C + 273 = 268 K
P2 = P1 T2 / T1
= 1.50 atm ( 268 K ) / 293 K
= 1.37 atm
Cancel out the units of K so that the remaining unit will be in atm.
