Question

The density of gasoline is about 6 pounds per gallon, and carbon accounts for nearly all the weight of gasoline Show that combustion of 1 gallon of gasoline produces about 20 pounds of CO₂ (the exact value is closer to 22 pounds)

Answer 1

Combustion reaction of pure carbon can be written as

C + O₂ ------->CO₂

molar mass of carbon = 12g/mol -----these are simply atomic mass

molar mass of CO₂ =16*2 +12 = 44g/mol

amount of gasoline used = 1gallon (6 pound)

amount of carbon used considering gasoline contains 100% carbon = 6pound

pound to gram conversion - 1pound = 453.592 grams

molecules of carbon used = 6 * 453.592 /12 molecules

molecules of CO2 produced = molecules of carbon used

6*453.592/12 = amount of CO2 produced in grams/molar mass

6*453.592 = amount of CO2 produced in pounds *453.592 /44

amount of CO2 produced in pounds = 6*44/12 = 22 pounds