crude oil and hydrocarbons

• fossil fuels are finite resources that will run out eventually, as they are produced at a slower rate than they are used
• Crude Oil is the remains of tiny marine organisms from millions of years ago. Heat and pressure + the absence of oxygen turn the remains into a complex mixture of thousands of hydrocarbons, carbon atoms are joined in chains/rings.
• C(N)H2(N)+2 is the molecular formula for hydrocarbons, where N is equal to the number of Carbons.

  e.g Methane = CH4, Ethane = C2H6
• crude oil is not useful at first, it is sticky and dangerous. however, fractional distillation can be used to make thousands of different products
• Crude oil is extracted from underground, and it is then heated in a fractionating tower, the liquid then evaporates, and the vapour condenses at different temperatures. The fraction with the lowest boiling point comes out of the top (usually liquid light fractions), and the fractions with the highest boiling points come out of the bottom
• 1 - Gases boil at 20 degrees, used for domestic heating and cooking

  2 - petrol boils at 30 degrees, used for fuel for cars

  3 - Kerosene boils at 180 degrees, used for aircraft fuel

  4 - Diesel boils at 260 degrees, fuels trains and certain cars

  5 - Fuel oil boils at 300-400 degrees, used in power stations

  6 - Bitumen boils at temperatures over 350 degrees, used for roads and roofs
• Larger molecules with more carbon atoms down the fractionating column have higher boiling points
• as you move down the fractionating column, density increases, volatility decreases, and boiling point increases. larger molecules do not ignite easily
• larger molecules have high viscosity, so they are thicker
• hydrocarbons with a few carbon atoms are highly flammable