Aflexible container is put in a deep freeze. its original volume is 3.00 m3 at 25.0°c. after the container cools, it has shrunk to 2.00 m3. its new temperature in degrees celsius is

To solve this we assume that the gas inside the balloon is an ideal gas. Then, we can use the ideal gas equation which is expressed as PV = nRT. At a constant pressure and number of moles of the gas the ratio T/V is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows:

T1 / V1 = T2 / V2

T2 = T1 x V2 / V1 

T2 = 25 x 3 / 2

T2 = 37.5 degrees Celsius