Compressed air can be pumped underground into huge caverns as a form of energy storage. The volume of a cavern is7.5 × 105m3, and the pressure of the air in it is7.1 × 106Pa. Assume that air is a diatomic ideal gas whose internal energy is given by U = (5/2)nRT. If one home uses 30.0 kWh of energy per day, how many homes could this internal energy serve for one day?