In: Physics
A hot air balloon has a total mass of 750 kg (not including the air in the balloon) and holds a volume of 2.8 x 10^6 L of air. Assume the density of the air outside the balloon to be 1.2 kg/m^3 at a temperature of 20 degrees C and the air pressure is 101.3 kPa inside and outside the balloon. What is the minimum temperature for the air in the balloon to allow for the balloon to float? You can assume the air in the balloon to be an ideal gas and you must consider the mass of the air in the balloon as part of the total mass. Also, assume the molar mass of air to be 29 g/mol. (The answer is 379 K. Please show work.)