You blow up a spherical balloon to a diameter of 50.0 cm until the absolute pressure inside is 1.25 atm and the temperature is 22.0o C. Assume that all the gas is N2, of molar mass 28.0 g/mol. (a) Find the mass of a single N2 molecule. (b) How much translational kinetic energy does an average N2 molecule have? (c) How many N2 molecules are in this balloon? (d) What is the total translational kinetic energy of all the molecules in the balloon?

Solution 71P Step 1 : Diameter of the balloon = 50.0 cm Radius = r = d/2 = 50/2 = 25 cm = 0.25 m Pressure inside balloon P = 28.0 g/mol 0 Temperature T = 22 C = 273 + 22 = 295K Molar mass = m = 28.0 g /mol