Sunday, April 12, 2009

“life lesson #4

“life lesson #4, consider a gassy truck” makes visible the invisible. The amount of CO2 emitted by automobiles is reported in terms of tons. The unit, “tons of a gas” is impossible for me to imagine. To put that amount in terms that I could “see” (albeit CO2 is a colorless gas), I chose to work with the unit "DGWGN equivalent" which is the volume of my truck as described by a life scale inflatable of my GMC Sonoma pickup.

to calculate the volume of CO2 this truck produces in driving an average of 15,000 miles per year:

Question: How much CO2 does my truck, DGWGN, produce per year?

Average milage/year 15,000
Volume (cubic feet) of DGWGN 150
Fuel Consumption (mi./gal) 20
Volume (gal) of gas consumed/year 750
Density of gasoline (grams/gal) 2.791
% Carbon /1 gal. of gasoline 85.5%
1 cubic meter 35.31 cubic feet
1 mole of a pure substance is the mass of the material in grams (g) that is
numerically equal to the molecular mass in atomic mass units.
Boyles Law – 1 mol of an ideal gas (not compressed) at STP occupies 22.4 liters

Calculation for volume of CO2 produced from 1 gal gasoline

1) Mass of CO2 from 1 gal of gasoline
= 8.75 kilograms CO2/gal of gas

2) Volume of 1 kg of CO2
= 509 liters CO2/ kilogram CO2
convert to cubic meters = 0.509 cubic meters/kilogram CO2
convert to cubic feet = 17.92 cubic feet/ kilogram CO2

3) Volume of CO2 from 1 gal of gasoline
= 157.2 cubic feet of CO2 / gal of gas

4) Volume of CO2 produced by DGWGN / year
= 157.2 cubic ft CO2/gal times 750 gal
= 786

Answer: 786 DGWGN Equivalents of CO2

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