Asample of gas occupies 7.80 liters at 425 c? what will be the volume of the gas at 35 c if the pressure does not change?

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 = 308.15 x 7.80 / 698.15

V2 =3.44 L