Solution

Calculate the rms velocity of hydrogen molecules at standard temperature and pressure (STP). Density of hydrogen at STP: $\rho = 8.957 \times 10^{-2}\,\mathrm{kg\,m^{-3}}$. Density of mercury $= 13600\,\mathrm{kg\,m^{-3}}$, $g = 9.8\,\mathrm{m\,s^{-2}}$.