[Utah-astronomy] Is this right? (OT)

I'm sitting here fighting with the one non-Mac machine I own (not sure who is winning at the moment) and listening to BBC. They just had a Yank on talking about energy consumption and pollution and at one point stated that "burning 6 gallons of gasoline will produce 20 pounds of CO2." Any of the science whizzes here care to say if that's right or not? I'm having trouble imagining how burning 6 pounds of gasoline can produce 20 pounds of CO2. Patrick