General information on oil

The oil is a liquid natural brown, more or less viscous. It is a mixture of hydrocarbons , compounds of carbon and to hydrogen only. Conventional oil contains other elements in varying proportions (usually around 15%). We can find traces of sulfur , of nitrogen , of oxygen , the metal ( iron , nickel ...) and the salt water .

The origin of the word comes from the Latin petra oleum (rock oil), because it was considered as such. 

Today, oil is everywhere: chemistry , energy , food. It has long been used by humans, but its dominance is relatively recent.