ABSTRACT
A large number of the materials and items we use daily are the result of extraction and/or separation from a basic mixture that contains a number of discrete components. As an example, one need only consider the gasoline that is so freely available and that we take for granted. This fuel is not a single, simple substance; rather, it is only one of many other important components-not all of them exclusively fuelscontained in the evil-smelling crude oil that has lain over many centuries in the Earth's crust. The origin of the oil goes back to countless billions of living animals (plankton and other marine life) who were trapped and killed by the movement of the crust caused by earthquakes and as a result subjected to increasing temperature, pressure, and the exclusion of oxygen. The combined effect of the enclosing rock substances and these two parameters is mainly responsible for the gradual transformation of the dead animals over the ages into the crude oil we know today. Vegetation in the form of countless thousands of trees and other organic substances also was not left untouched. It, too, was subjected to entrapment and treatment by the increasing temperature, pressure, and oxygen exclusion, resulting in other materials being formed. The most common and well known of these materials is coal. Most theories on the origins of crude oil and coal appear to postulate a very close affinity between the two. Initially, coal was likely exploited as a means of providing heat, but later it became the source of other useful products as technology advanced. It is also documented that some ancient tribes found crude oil on the surface of the Earth and used it in the first instance for medicinal purposes and for providing light. They found it readily and easily transportable and very easy to ignite. Unbelievable as it may appear, coal is still the largest raw material source from which chemicals and fuel can be extracted. Both of these raw materials are made up largely of the elements carbon and hydrogen and thus fall under the general heading of hydrocarbons.
