Organic Chemistry - Fuels

Objective: State that petroleum is a mixture of hydrocarbons

Petroleum is a naturally occurring, complex mixture of hydrocarbons. Hydrocarbons are organic compounds made up entirely of carbon and hydrogen atoms. These hydrocarbons vary in their chain lengths and arrangements, resulting in a wide range of fuel types derived from petroleum.

The composition of petroleum is not uniform; it's a complex blend of different hydrocarbons. This mixture is what gives us various fuels like petrol, diesel, and liquified petroleum gas (LPG).

Types of Hydrocarbons in Petroleum

The hydrocarbons found in petroleum can be broadly classified into:

• Alkanes: Saturated hydrocarbons with single bonds only.
• Alkenes: Unsaturated hydrocarbons with at least one double bond.
• Alkynes: Unsaturated hydrocarbons with at least one triple bond.
• Aromatic hydrocarbons: Unsaturated hydrocarbons containing a ring of carbon atoms with alternating double bonds (e.g., benzene).

Table: Composition of Petroleum

Hydrocarbon Type	Typical Percentage in Petroleum
Alkanes	50-70%
Alkenes	5-15%
Alkynes	< 1%
Aromatic Hydrocarbons	5-25%

The specific proportions of these hydrocarbon types vary depending on the source of the petroleum.

The presence of different types of hydrocarbons determines the properties and uses of the resulting fuels.