Cracking Hydrocarbons

Question 1

What is Cracking and why is it used?

Answer 1

Cracking is the process of breaking bigger molecules into smaller ones via thermal decomposition

These smaller ones are usually much more useful than the bigger molecules

C8 H18 (Octane - Petrol) can be turned into C4 H8 (Butene) + C4 H10 (Butane)

Question 2

What colour do Alkenes (molecules produced by cracking that are unsaturated and have a double bond) turn bromine water?

Answer 2

Alkenes turn bromine water from orange to colourless.

This means we can test for them using this water.

Question 3

How do we break down / crack large hydrocarbons?

Answer 3

We break down large hydrocarbons with thermal decomposition. This is done by hearing them and passing them over a catalyst. This is called cracking

Question 4

What is a catalyst?

Answer 4

A catalyst is a material the molecule we want to crack has to be passed over.

Question 5

What are the molecules produced by cracking with a double bond that are unsaturated?

Answer 5

Alkenes are molecules produced by cracking. They have a double bond and are saturated.

We can test for them using bromine water

Question 6

What is thermal decomposition?

Answer 6

Thermal decomposition is the process of cracking larger molecules into smaller, more useful ones