Question: Nitrogen gas (N2, M = 28u) at room temperature (300K) and atmospheric pressure has a density of 1.25kgm-3. The measured root mean square velocity of a N2 molecule is vrms ≈ 500m/s.
a. What is the average energy of a N2 molecule under these conditions? Express your answer in J as well as eV.
b. At the same temperature and pressure, what is the average energy of a helium atom (M = 4.0u)?
c. Under these conditions, what is vrms for a helium atom?
d. Figure shows a plot of the logarithm of pressure (ln P) in a jar vs. time for an experiment in which gas leaks out of the jar through a tiny hole into a vacuum. The heavy solid line shown is for N2. Which of the two dotted lines (A or B) best approximates the behavior of helium under the same experimental conditions? Explain briefly
Fig. - Logarithm of pressure vs. time for gases leaking into a vaccum