|The question is about oil or petroleum. Does this
come from animals or also from plants. Why is
petroleum a liquid and coal solid? Is it that
coal is older and pressed down longer?
Oil and petroleum can come from any kind of
organic material if it is well preserved
throughout the history of the rock. There are
three types of organic material, the one that
comes from plants, the one that comes from forams
(also called phytoplancton and zooplancton) these
are little bugs that float in the sea water, and
the one that is a combination of these two, in
other words a combination of plants and floating
bugs.A rock that contains organic material is also
called "Black Shale". When this rock is buried and
undergoes high pressures and temperatures, it
expels oil. If the burial continues and the
temperature increases, it will expel gas (the one
some people use to cook). It the rock gets even
hotter, the rock itself may convert into coal.
Think of the oil as the liquid expelled from the
black shale, and coal as the black shale that has
been heated very much!
Nobody is sure exactly where oil comes from. It is
composed of a mixture of the elements carbon and
hydrogen, and it is supposed that organic
matter(containing both elements) that is heated by
the Earth's interior creates oil. If this is true,
then both plant and animal matter would make oil,
because both contain hydrogen and carbon. Other
possible sources include comets.
compressed plant matter and has not been subjected
to the same amount of change as oil has, if oil
indeed is once-living matter. You can still see
roots and the like in blocks of coal, even. Coal
is solid because it has not been significantly
altered chemically and because roots, twigs, etc.
are solid.The phase of petroleum actually depends
on the number of carbons per molecule: methane (in
a gas stove and has one carbon) is a gas; gasoline
(which has six to eight carbons) is a liquid; tar
(which has fifteen ormore carbons) is a solid.
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