C1a+3+Crude+Oil

Use this material to go back over the Crude Oil section of C1a. The main points to remember are:
 * Crude oil is a mixture of different compounds - mainly **hydrocarbons** (molecules made only of carbon and hydrogen)
 * Straight out of the ground, crude oil is no use at all, but we can seperate out the useful stuff using **distillation**
 * Crude oil is commonly separated out using **fractional distillation** (see the diagram below). Hydrocarbons which have really long chains have a high boiling point, and come off at the bottom of the column. The smaller the chain, the lower the boiling point and the higher up the column it condenses
 * The hydrocarbons produced are known as **alkanes** and have the general formula CnH2n+2. For example, Ethane is C2H6
 * Buring these hydrocarbons has consequences for the envirnoment due to the polluting chemicals produced... **Acid Rain**, **Global Warming** and **Global Dimming** are just some of the problems



Check out the powerpoints for more info: