For 10 points, name this greenhouse gas exhaled by humans, with formula CO2.
The Keeling Curve plots the atmospheric concentration of this compound. Its supercritical form is used to decaffeinate coffee beans, and it reacts with ammonia to form urea or with water to form carbonic acid. This linear molecule with two (*) double bonds is produced alongside water in combustion reactions. At room temperature this gas sublimes from its solid form, called dry ice. For 10 points, name this greenhouse gas exhaled by humans, with formula CO2.
The Keeling Curve plots the atmospheric concentration of this compound.
carbon dioxide (accept CO2 before the end; do not accept "carbon monoxide")