Show Calculations Please Suppose the average SUV is driven 12,000 miles per year
ID: 893240 • Letter: S
Question
Show Calculations Please
Suppose the average SUV is driven 12,000 miles per year with a fuel efficiency of 15 mpg. Gasoline contains 5.25 lbs of carbon per gallon, all of which ends up as CO_2 when burned, and it has an energy density of 120,000 Btu/gal. The short tons (2000 lb) of CO_2 emitted per SUV per year are most nearly equal to: 7.5 7.7 8.5 8.7 The Btus of energy consumed per SUV in the year are most nearly equal to: The ratio of g C emitted per unit of energy as g C/Btu is most nearly equal to:Explanation / Answer
SVU is driven for 12,000 miles/yr with 15 miles per gallon
=12,000/15 gallons/yr= 800 gallons/yr
number of carbon =5.25 lb/gallon
lbs of Carbon =800*5.25 lb=4200 lb/yr=4200*0.4535 kgs/yr = 1904.7 kgs 1904700 g/yr
The reaction is C+ O2---> CO2
12 lbs gives 44 lbs CO2
42000 lb/yr gives 4200*44/12=15400 lb/yr= 15400/2000 tons/yr =7.7 tons/yr (B is correct)
b)Btu of energy consumed =120000 but/gal*800 gal/yr =96000000btus=96*106 btu /yr nearly 100X106 btu ( B is correct)
c) energy consumed = 100*106 btu/yr
Carbon emitted = 1904700 g/yr
gms of Carbon emitted/ btu =1904700/(100*106) =0.02 (A is the correct answer)