Crude oil, hydrocarbons and alkanes

• Crude oil is the remains of plankton and other living material buried in mud millions of years ago.
• Crude oil is made of hydrocarbons
• Today crude oil is found in rocks and people have to drill underground to get it.
• Crude oil is a finite resource, which means it will eventually run out
• Hydrocarbons are compounds made from only carbon and hydrogen atoms.
• In crude oil, most of the hydrocarbons are a type called alkanes.
• Crude oil is made up of a mixture of different hydrocarbons
• Alkanes are hydrocarbons with the general formula CnH2n+2.
• For example, ethane is an alkane with the formula C2H6
• Alkanes are usually drawn as a chain of carbon atoms surrounded by hydrogen atoms.
• The first 4 alkanes are called methane, ethane, propane and butane.
• All the carbon and hydrogen atoms are connected by single covalent bonds.
• Crude oil is a mixture of hydrocarbons.
• The mixture of hydrocarbons in crude oil can be separated to form useful products.
• The different groups of hydrocarbons are called fractions
• The hydrocarbons in a fraction all have asimilar number of carbon atoms.
• Fractions are separated using a process called fractional distillation.
• Fractional distillation separates hydrocarbons
• The first step in fractional distillation is to evaporate the crude oil by heating it causing most of the hydrocarbons to evaporate and rise up the fractional distillation column.
• The fractional distillation column is hotter at bottom and cooler at the top
• Short hydrocarbons have lower boiling points because it take less energy to break those bonds.
• short hydrocarbons condense near the top of the column where it is cooler because they have low boiling points.
• Long hydrocarbons have higher boiling points.

  As a result, long hydrocarbons condense nearer the bottom of the column.
• Many of the fractions produced from fractional distillation are used as fuels.
• Examples of these fuels are petrol, diesel oil, kerosene, heavy fuel oil and liquefied petroleum gas
• Other fractions are used to make chemical products for everyday life.

  For example, some fractions are used to make solvents, lubricants, detergents andpolymers
• petrochemical industry produces solvents, lubricants, polymers and detergents
• Alkanes contain only single C-C bonds.
• A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula
• Physical methods are used to separate mixtures. In this case, fractional distillation is used
• Saturated compounds only contain single C-C bonds.
• The general formula for alkanes is CnH2n+2.
• Kerosene is the fraction of crude oil used as a fuel for aircraft.
• The different fractions cool and condense at different levels because they have different boiling points. The fractionating column is hotter at the bottom and cooler at the top.
• The fractions cool and condense at different levels in the fractionating column.
• Different fractions have different boiling points, so they can be separated using fractional distillation.
• Hydrocarbons with 4 carbon atoms start with but-.
• Increasing the chain length of alkanes leads to molecules that are less flammable and less volatile
• Crude oil is a mixture of different compounds. Most if the compounds are hydrocarbons
• Crude oil is a finite resource