crude oil/ hydrocarbons

• Hydrocarbons are compounds that contain hydrogen and carbon atoms only.
• Crude oil is a finite resource that is found in the Earth’s crust. It is the remains of organisms that lived and died millions of years ago
• Crude Oil is an important source of energy and is used to make fuels such as petrol and diesel.
• Solvents, lubricants and detergents are other useful substances made from compounds found in Crude oil
• Fractional distillation is used to separate crude oil into simpler, more useful mixtures.
• In fractional distillation a mixture of several substances, such as crude oil, is distilled and the evaporated components are collected as they condense at different temperatures.
• During the fractional distillation of crude oil:

  • heated crude oil enters a tall fractionating column, which is hot at the bottom and gets cooler towards the top
  • vapours from the oil rise through the column
  • vapours condense when they become cool enough
  • liquids are led out of the column at different heights
• Small hydrocarbon molecules have weak intermolecular forces, so they have low boiling points.
• Long hydrocarbon molecules have stronger intermolecular forces, so they have high boiling points. They leave the column as hot liquid bitumen.
• Viscosity is a measure of how difficult it is for a substance to flow - the higher the viscosity, the 'thicker' it is.
• hydrocarbon + oxygen → carbon dioxide + water