What Is Crude Oil? How is it used in Chemistry?

Crude Oil is also referred to as Petroleum from the greek word "petra"- meaning rock, and "oleum" meaning oil. During the early years of crude oil production, it was often sought after and referred to as "rock-oil."

Crude Oil is classified as a Hydrocarbon which is any organic compound composed of primarily hydrogen(H) and carbon(C) with traces of small amounts of sulfur (S), nitrogen(N) and oxygen(O).  They can be put together in different ratios to create different substances.  Petroleum is one of the most common hydrocarbons.  During the refining process of petroleum, one hydrocarbon is often converted to another, more useful kind. Some of these useful mixtures include cooking gas, gasoline, kerosene, benzine, lubricating oils, etc. Many hydrocarbons are useful as fuels because, as we learned in class, they combust by burning in air and creating carbondioxide (CO2) and water (H2O). A common hydrogen-carbon ratio that is found is 11-15% hydrogen and 82-87% carbon.

The picture above gives examples of what hydrocarbons look like.         Click here to connect to this site!

Petroleum is a thick, flammable and usually dark colored liquid fuel that is found generally below the earth's crust, but occasionally in springs and pools at the surface.  Petroleum oil forms in a very slow process and is derived from plant and animal material which was embedded in sedimentary beds millions of years ago. It was covered with layers of sedimentary rock which prevented the oxidation and distillation of it, although it increased the heat and pressure and caused partial distillation, resulting in the formation of kerogen which further seperates into oil and gas when it's heated at temperatures above 100 degrees celcius. If the oil becomes buried too deeply and becomes exposed to temperatures higher than 200 degrees celcius, the bonds between the oil molecules become weaker and cause the oil to decompose.  (We learned about the process of decomposition of a compound in class.)