Misconception
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Reality
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Octane is an additive to gasoline; it is not a major
portion of it
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Octane makes up the majority of gasoline; between
80 and 90% in most standard automotive forms. It is a primary component
of all standard gasolines. Alternative fuel mixes, containing chemicals
such as Ethanol (derived from corn) still generally contain a good deal of
octane if they run in standard engines.
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Using a higher octane gasoline causes improved
engine performance
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Engines must be specially designed to gain benefits
from higher octane; for other engines, it is only a waste of money.
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Leaded gasoline was used because lead acted as
a cooling agent for the engine valves
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Lead does do this, but it doesn't do this very effectively.
Its primary purpose was as a cheaper replacement for higher octane percentages.
Many cars designed to run on leaded gasoline can run fine on standard, unleaded
gasoline.
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Chemicals with the same number of each atom and
with the same generic name have the same structure and properties, whereas
ones with different numbers and names have different properties
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Chemicals with the same generic name, such as the
two forms of Octane, are more different from each other than n-Octane is
from n-Heptane, at least as far as combusting properties. Structure can
be just as important as content, at least in some situations.
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The burning of fossil fuels produces harmful chemicals
(other than carbon dioxide, such as carbon monoxide)
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Chemicals like carbon monoxide are only produced
when burning is not completed. Because of the limited time in the cylinder,
all of the gas cannot burn before it is released, and the unburnt gas is
often in the form of these chemicals. Emissions control systems on cars try
to complete the burning process.
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