Question

Carbon fossil fuels are utilized to power our vehicles, make oil, and even t-shirts. The EPA has determined that a car transforms a gallon of octane (C8H18) to 33.7 kWh (kilowatt*hours, an expression of energy) in order to power a vehicle.

1. Provide the balanced equation for the complete combustion of octane.

2. If a truck is able to drive 360 miles on a tank of octane (22 gallons) how much energy is needed to move the vehicle one mile? What mass of CO2 is produced per gallon of octane? (the density of octane is 0.703 g/mL)

3. According to the L.A times there are 253 million cars on American roads. Assuming that each car is driven 50 miles each day, five days a week determine the mass and volume of the CO2 produced and mass of octane needed to power them for a year (assuming 20 miles per gallon)?

Answer 1

1. The balanced reaction is 2C₈H₁₈+25O₂--->16CO₂+ 18H₂O

2. 1 gallon of octane corresponds to 33.7 KWh

22 gallonns required 33.7*22= 741.4 KWh

360 miles require 741.4 KWh

1mile require 741.4/ 360 =2.059 KWh

Gallon refer to 3.785 L

22 gallons refer to 22*3.785 L =83.27 L=83.27*1000 ml =83270ml

Density of octane =0.703 g/ml Mass of octane =83270*0.703=58539 g

Molecular weight of octane = 114g/mol, molecular weight of CO2 =44

As peth the balanced reaction 2moles of Octane produces 16 moles of CO2

2*114=228 gm of octane produces 16*44=704 gm of CO2

58539 gm produce 58539*704/228 gm of CO2 =180752 gm of CO2 = 180.752 Kg

1 gallon of octane produces 180.752 kg fof CO2

3. Miles per gallon =20 miles

Each car runs for 50 miles a day , one car requires 50 miles

50 miles require =50/20 =2.5 gallon of octane / day = 2.5*5 gallonn/week =12.5 gallons/week=12.5*365 gallons/year=4562.5 gallons/year/car

This is the requirement per car . There are 253million cars =253*10⁶ cars required

253*10⁶* 4562.5 gallons/ year r= 1.154*10¹² gallons

1 Gallon of octane produces 180,752 kg of CO2

1.154*10¹² gallons produce 2.09*10¹⁴ kg of CO2 in a year