Hydrocarbons from the Earth’s crust

1. Chemistry 121/122 Hydrocarbons from the Earth’s crust

2. Natural Gas • Made up of hydrocarbons with low molar masses (mostly methane) • Good for combustion because it burns with a hot, clean flame • Natural gas is separated into its hydrocarbon components through liquefaction • They are sold as liquid petroleum gas (LPG)

3. Petroleum • Otherwise known as crude oil • Most are straight chain and branched chain alkanes • Amount of carbon can vary from 1 – 40 • The mixture has to be separated, or refined, in order to be useful • This begins with distillation into fractions according to boiling points

4. Cracking • Due to the demand of gasoline, chains of carbon that do not fall under its criteria need to be broken, or cracked, into more useful molecules • Cracking can occur with catalysts and heat • Some of these molecules are also used to manufacture plastics and paints

5. Coal • Vegetation died and became peat • Peat can be used an an inexpensive fuel • If left in the ground, it can eventually turn into lignite, or brown coal, then bituminous coal, and ultimately, hard coal • All have increasing amounts of carbon and lesser amount of water • Obtained by mining • Mostly composed of aromatic compounds of high molar mass