Oil: Refining
Crude oil is refined into products such as gasoline, asphalt, and waxes by a process called fractional distillation.
During the process, the parts, or fractions, of crude oil are divided out successively by their increasing molecular
weight. For instance, gasoline has a low molecular weight and vaporizes at a fairly low temperature. This means
that at the appropriate temperature, while all of the rest of the oil is still in liquid form, gasoline may be separated
out. The remaining oil goes through the same process at a slightly higher temperature, and jet fuel is divided out.
Repeating the distillation process several times will separate out several constituents of crude oil, which are then
processed and put to a wide range of uses.