C9 - Crude oil and fuels

What is crude oil?

Crude oil is a finite resource found in rocks. Crude oil is the remains of an ancient biomass consisting mainly of plankton that was buried in mud. Crude oil is a mixture of a very large number of compounds.

What are hydrocarbons?

Compounds made only from hydrogen and carbon atoms

What is an alkane?

Saturated Hydrocarbons.


1. Only carbon and hydrogen atoms.
2. Only single bonds (alkanes have no double bonds).

What is the general formula of an alkane?

How is crude oil separated and by what process?

Crude oil is separated into fractions by fractional distillation

The properties of each fraction depends on …?

The size of hydrocarbon molecules in it

Why do lighter fractions make better fuel?

They ignite more easily and burn well, with cleaner (less smoky) flames

What do the terms viscosity and volatility mean?

viscosity - how easily it flows

volatility - the tendency to turn into a gas

What happens when hydrocarbons are burnt in the air?

The carbon and hydrogen in the fuel are completely oxidised.

They produce carbon dioxide and water.

How can you test for the gases formed in the complete combustion of hydrocarbon?

The carbon dioxide turns limewater cloudy

water turns blue cobalt chloride paper pink (or white anhydrous copper sulfate blue)

What does incomplete hydrocarbon combustion produce?

Carbon monoxide - a toxic gas

What is cracking?

A process which breaks large less useful hydrocarbons into smaller more useful hydrocarbons

what are the two types of Cracking?

catalytic cracking - by passing the vapours over a hot catalyst ,

steam cracking - mixing them with steam and heating them with a very high temperature.

What does cracking produce?

Saturated hydrocarbons - alkanes used for fuel

unsaturated hydrocarbons - alkenes

What is a test for an unsaturated hydrocarbon?

Alkenes (and other unsaturated compounds containing carbon-carbon double bonds) react with orange bromine water turning it colourless

What are isomers

Isomers are molecules that have the same molecular formula, but different structural formulas, this means they are made of the same atoms, but the atoms are arranged differently.

What is the definition of a homologous series?

A homologous series is a group of organic compounds that have similar chemical properties, due to them having the same functional group.

What is a Feedstock?

a raw material used to provide reactants for an industrial reaction

What is a petrochemical?

a substance made from crude oil via chemical reactions