On Sun, Aug 19, 2012 at 4:43 PM, David Roberson <dlrober...@aol.com> wrote:
> I doubt that the pressure would change very much in the case of excited > atoms since this is a gas. The pressure depends more upon the number of > atoms than their size. > While true, that is different from the statement "I doubt that any change in the pressure would be due to any change in the size of the atoms." The second question probably depends upon whether or not the gas is heated > up by the ionization. If kinetic energy is given to the gas atoms, they > will move faster and the pressure would rise. > Again, that is different from the statement, "The ionized gas pressure would not change due to ionization per se." > The third question is complex. If work was done by the gas during the > process before the gas neutralized, then the pressure would be less along > with the temperature. > Then consider work done compressing another gas reservoir. Certainly we can expect that the ionized gas chamber would decrease in temperature and pressure as it increased in volume while doing work against the other gas reservoir. However, this doesn't do us any good because when the electrons fall back to their ground state and neutralize the positive ions, the energy originally input to ionize is re-emitted as photons of, presumably(?) the same total energy as that originally required to ionize the gas atoms.
