Mercury is a liquid at room temperature and pressure, but its vapor is present in the atmosphere from natural sources, such as volcanoes, and from human ("anthropogenic") activities such as coal burning and gold mining. Elemental Hg becomes extremely toxic when oxidized to Hg (I) or Hg (II) compounds.
(a) The Environmental Protection Agency has estimated that 119 tons of mercury are currently emitted to Earth's atmosphere annually due to human activities; this has decreased significantly from the mid-1970s before pollution controls were in place. What volume would the 119 tons of mercury occupy if it were a pure vapor at 1.00 atm and 298 K?
(b) Geological records suggest that before the Industrial Revolution began in 1750, the baseline level of atmospheric Hg was 35 ppb (parts per billion, by volume, or 35 L Hg for every 109 L of air); current estimates are 245 ppb. For an estimated atmospheric volume of 51 x 1012 m3, calculate the number of moles Hg estimated to be in the atmosphere today.