C6 - Global Challenges

A compound made up of only hydrogen and carbon atoms

A group where each compound has the same general formula with each successive member differing by CH2. All compounds have the same properties.

CnH2n+2

They react in a process called combustion. Complete combustion: Alkane + O2 –> CO2 + H2O 2C2H6 + 7O2 —> 4CO2 + 6H2O Incomplete combustion: Alkane + O2 –> CO + H2O 2C2H6 + 5O2 —> 4CO + 6H2O

It is a fossil fuel. It is a non-renewable resource - it is being used up faster than it is being formed

They are formed from the remains of dead organisms that lived millions of years ago - chemical reactions over time turned them into crude oil

Using fractional distillation

A homologous series of hydrocarbons with at least one carbon-carbon double bond

CnH2n

C=C

An atom or group of atoms which give a molecule its chemical properties

• React bromine water with the alkene • Mixture should turn colourless if alkenes are present

Cracking is a chemical process which converts large alkanes into smaller alkanes and alkenes For example: C7H16 –> C2H4 + C5H12 Heptane –> ethene + pentane

High temperature (600-700°) Hot catalyst of alumina or silica

Smaller hydrocarbons are more useful to use as: • They have lower boiling points • They flow more easily • They are easier to ignite Cracking also helps the supply to meet the demand

They are made from an additon reaction in which molecules join together to make 1 big molecule

Methanol Ethanol Propanol Butanol

Methane Ethane Propane Butane

Ethene Propene Butene

CnH2n+1OH