Petrol is made from crude oil by removing hydrocarbons and carbon atom chains through a process known as distillation. Usually, this process takes place at an oil refinery. Distilling petrol relies on gradually increasing the temperature of crude oil to break apart and get rid of these chains. The product that is left behind is a pure and usable form of petrol.
According to How Stuff Works, the oil that is pumped out of the ground is usually not ready to be used in vehicles. It is called crude oil, and it must be processed before it can act as fuel for vehicles and industrial equipment. In order to convert crude oil into petroleum, it must be heated. This is because crude oil contains different chains of hydrocarbons and carbon atoms. These chains span a variety of different possible lengths. Each different length chain has its own set of chemical properties and characteristics. However, if a sample of crude oil is heated to a sufficient temperature, these chains can be separated by their vaporizing points. Once these chains have been separated, chains of a certain length can be blended together. This can yield a number of different liquids, including kerosene and lubricating oil, in addition to petrol.