Crude Oil and Fuels - Cracking hydrocarbons

Question 1

Why crack hydrocarbons?

Answer 1

• Heavy fractions are made of larger molecules which are not in high demand
• Difficult to vaporise and do not burn easily and are poor fuels

Question 2

How are hydrocarbons cracked?

Answer 2

-Takes place in an oil refinery in steel vessels called crackers
-A heavy fraction is vaporised and then either:
>passed over a catalyst
>mixed with steam and heated at a very high temperature
-Hydrocarbons are cracked as thermal decomposition

Question 3

What are the products of cracking hydrocarbons?

Answer 3

-Saturated hydrocarbons and unsaturated hydrocarbons

Question 4

What is an alkene?

Answer 4

• Unsaturated hydrocarbon which contains a carbon-carbon double bond
• It has a general formula of C(n)H(2n)
• More reactive than alkanes
• Turns orange bromine water colourless