Academic Subjects
➤
Chemistry
➤
General Chemistry
➤
Chemical Reactions
➤
Car Emission
Automobiles are often implicated as contributors to global warming because they are a source of the greenhouse gas CO
2
How many
pounds
of CO
2
would your car release
in a year
, if it was driven
150. miles
per week?
In your calculations, assume that gasoline is octane (molecular formula C
8
H
18
)
and that its burned completely to CO
2
and H
2
O in the engine of your car.
Also assume that the car averages
25.3 miles
per gallon and the density of octane is 0.703 g cm
-3
Let's take this step by step
Total miles driven per year
(
150 mi
)
/
(1
week
)
(52
weeks
)
/
(1
year
)
= 7800
mi
/
year
Total fuel usage per year
(7800
mi
)
/
(1
year
)
(1
gal
)
/
(
25.3
mi
)
= 308.3
gal
/
year
Now, let's write the balanced equation for this combustion
2 C
8
H
18
+ 25 O
2
⇒
16 CO
2
+ 18 H
2
O
And finally, we convert
1 gal = 3 785.14 g
1 g = 0.0022 lbs
and the density info in the question is there to throw you off
gal to g ↔ g to mole ↔ mole to mole ↔ mole to g ↔ g to lbs
(308.8
gal
C
8
H
18
)
/
(1
year
)
(3 785.14
g
C
8
H
18
)
/
(1
gal
C
8
H
18
)
(1
mole C
8
H
18
)
/
(114.26
g C
8
H
18
)
(16
moles CO
2
)
/
(2
moles C
8
H
18
)
(44.01
g CO
2
)
/
(1
mole CO2
)
(0.0022
lbs
CO
2
)
/
(1
g
CO
2
)
=
7 911.45
lbs
CO
2
/
1
year
The car, if driven 150. mi/week, will release 7.91 x 10
3
lbs of CO
2
per year