A student reduces the temperature from a 300 cm3 balloon from 60°C to 20°C. What will the new volume of the balloon be?

264 cm3

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

V2 = T2 x V1 / T1

V2 = 293.15 x 300 / 333.15

V2 = 263.98 cm^3