  We use thermodynamic calculations to model atmospheric chemistry on
terrestrial exoplanets that are hot enough for chemical equilibira between the
atmosphere and lithosphere, as on Venus. The results of our calculations place
constraints on abundances of spectroscopically observable gases, the surface
temperature and pressure, and the mineralogy of the surface. These results will
be useful in planning future observations of the atmospheres of
terrestrial-sized exoplanets by current and proposed space observatories such
as the Hubble Space Telescope (HST), Spitzer, James Webb Space Telescope
(JWST), Terrestrial Planet Finder, and Darwin.
