Hydrocarbons

Hydrocarbons, are compounds that are made from hydrogen and carbon. They store a lot of energy and are highly used around the world for different purposes:

Wax
Gas
Petrol/diesel
Building roads

Most of these uses are for energy.

Phase 1 science only studies Alkanes, which are usually written in formula C_nH_2n+2 where n - number of carbon atoms.

Fractional distillation

Fractional distillation is the way of extracting specific compounds from a mixture. It is done by separating the compounds by their bioling point. Simplest fractional distillation is done with Alkanes, where fractional column is made up of specific elements.

Apparatus

Fractional column (for alkanes)

Name	Boiling point range (Celcius)	Hydrocarbon chain
LPG (propane, butane, methane)	< 25	C₁H₄ - C₄H₁₀
Pertol	40 - 100	C₄H₁₀ - C₁₂H₂₄
Kerosene	140 - 250	C₁₃H₂₈ - C₁₅H₃₂
Diesel	220 - 350	C₁₅H₃₂ - C₁₉H₄₀
Lubricating oil	> 350	C₂₀H₄₂ - C₃₀H₆₂
Fuel oil	> 400	C₃₀H₆₂ - C₄₀H₈₂
Bitumen	> 400	> C₅₀H₁₀₂

Intermolecular forces

Different boiling points of each compound mean that they have different strengths. Strength is defined by the number of atoms in the hydrocarbons. The more complex the structure, the more atoms there are. The more atoms, the more forces exist between each molecule, giving a resultant force higher for the molecule, with one atom added.
More intermolecular forces mean that there is higher resultant force and higher amount of energy needed to break them. Therefore, higher temperature is needed to reach the bioling point, where they are split up and can be easily extracted.