A sealed balloon is filled with 0.70 L of helium at 23C and 1.00 atm. The balloon rises to a point in the atmosphere where the pressure is 220 torr...

A sealed balloon is filled with 0.70 L of helium at 23°C and 1.00 atm. The balloon rises to a point in the atmosphere where the pressure is 220 torr and the temperature is -31°C.What is the change in volume of the balloon as it ascends from 1 atm to a pressure of 220 torr?