Concept explainers
Use Figure 5.6 to compare the energy released for the combustion of 1 gallon of ethanol and 1 gallon of gasoline. Assume gasoline is pure octane (C8H18). Explain the difference.
Hint: You will need to consider their densities.
Figure 5.6
Energy differences (in kJ/g) for the combustion of methane (CH4, n-octane (C8H18), coal (assumed to be pure carbon), ethanol (C2H5OH), and wood (presumed to be glucose). Carbon dioxide and water are formed in the gas phase.
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