Question

A weather balloon is filled with helium that occupies a volume of 5.27 10^4 L at 0.995 atm and 32.0°C. After it is released, it rises to a location where the pressure is 0.720 atm and the temperature is -12.7°C. What is the volume of the balloon at that new location?

Answer 1

ideal gas law:
pv = nrt

nr is mole times the ideal gas constant, these are both held constant (do not change value)
pv/t = nr

Then you can set the conditions before = after
pv/t = PV/T

before: (convert to Kelvin)
(0.995)(5.27x10^4) / 305

After: (convert to Kelvin)
(0.720)V / 206.3

solve for V , volume after.
(0.995)(5.27x10^4) / 305 = (0.720)V / 206.3
4.926 x 10^4 L = V