Homan R. answered 05/06/20
Experienced Science Tutor
Use the combined gas law P1V1/T1 = P2V2/T2
You did not provide units so I'm going to assume that the temperature is in degrees C.
1.) First convert degrees C to K
K = degrees C + 273.15
T1 = 21.7C + 273.15 = 294.85 K
T2 = -4.44C + 273.15 = 268.71K
2.) Set up your known equation by laying out your known variables to see if you need to convert any other units
P1 = 769 mmHg, V1 = 59.0 L, T1 = 294.85 K, P2 = 0.0635 atm, V2 = ?, T2 = 268.71 K
3.) We see that the units of pressure are not the same. Convert both to either mmHg or atm. In this case, I will put both units in atm. Use the conversion factor 1 atm = 760 mmHg
P1 = 769 mmHg x (1 atm / 760 mmHg) = 1.01 atm
4.) Set up your equation by plugging in variables and solve!
P1V1/T1 = P2V2/T2
(1.01 atm)(59.0 L) / 294.85 K = (0.0635 atm)(V2) / 268.71 K
(1.01 atm)(59.0 L)(268.71 K) / 294.85 K = (0.0635 atm) (V2)
V2 = 855.23 L
Hope this helps! Double check my calculations to make sure you are getting the same math but the logic here should be correct.