A container at 300 K contains H2 gas at a pressure of one atmosphere. At this temperature H2 obeys the Boltzmann distribution. Find to what temperature must the H2 gas be cooled before quantum effects become important and the use of the Boltzmann distribution is no longer appropriate? (Hint: Equate the de Broglie wavelength at the average energy to the average spacing between molecules, using the ideal gas law to compute the density.)