Driving 1000 miles a month is not unusual for a short-distance commuter. If your vehicle gets 19.70 mpg, you would use approximately 50.76 gallons of gasoline every month. If gasoline is approximated as C8H18 (density = 0.703 g/mL)...?

How many grams of carbon dioxide does your vehicle emit every month?

2 Answers
Oct 17, 2017

Each month, the car will produce 417 120 g of CO2

Explanation:

First, let's get all the unit sorted out.

Assuming this is a US gallon, it will be equivalent to 3785 mL, and since the density of octane (representing the gasoline) is 0.703 g/mL, the one gallon would be

3785mL×0.703gmL=2661g per gallon

You have used 50.76 gallons each month, so

50.76×2661=135072 grams each month.

The reaction that produces CO2 is

2C8H18+25O216CO2+18H2O

so, we need to change those grams of gasoline into moles of octane:

Moles = 135072g÷114gmol=1185mol

According to the reaction, we get 8 moles of CO2 for every 1 mole of C8H18, so the number of moles of CO2 produced will be

1185×8=9480 moles of CO2

Since each mole of CO2 has a mass of 44.0 g, the total monthly output of CO2 will be...

9480mol×44.0gmol=417120 g or 417.1 kg

Oct 17, 2017

About 4.171×105 grams of CO2 is emitted.

Explanation:

[Step1] First, calculate the volume of gasoline V to drive 1000 miles.

V=50.76 (gallons)
Assuming gallon to be the US gallon( 1 US gal = 3.785 L),
V=50.763.785=192.1 (L)

[Step2] Then, calculate the mass(g) and amount of substance(mol) of C3H8 (octane).

The mass is 192.1103 (mL) 0.703 (g/mL) =1.351×105 (g).

Since the molar mass of C8H18 (octane) is 128+118=114 (g/mol) , the amount of substance of octane is 1.351×105114=1.185×103 (mol)

[Step3] Calculate the CO2 emission.
The chemical equation for burning C8H18 is
2C8H18+25O216CO2+18H2O. Eight moles of carbon dioxcide is emitted per one mole of octane.

Thus the amount of substance for CO2 is 1.185×1038=9.480103(mol).
The molar mass of CO2 is 121+162=44.
Therefore, the mass of CO2 emitted in a month is 9.480×10344=4.171×105 (g).