C - Cracking Crude Oil

Question 1

After the distilled of crude oil, you’ve still got both long and short __________, just not all mixes together

Answer 1

Hydrocarbons

Question 2

What does cracking mean?

Answer 2

Splitting up long-chain hydrocarbons

Question 3

The longer molecules produced from fractional distillation are turned into smaller ones by a process called…

Answer 3

Cracking

Question 4

Why are the long chain hydrocarbons produced from fractional distillation not always useful?

Answer 4

Because they are thick and gloopy e.g tar

Question 5

Diesel is a long hydrocarbon, by cracking it, what sort of useful products can be made? (3)

Answer 5

Petrol
Paraffin (jet fuel)
Ethene (plastics)

Question 6

What is the process of cracking?

Answer 6

• Heat the long chain hydrocarbon atoms to vaporise it (turn it into gas) and break down molecules
• the vapour is passed over a powdered catalyst (aluminium oxide) at 400°c-700°c
• the molecules split

Question 7

An alternative way of cracking long-chain hydrocarbons is to mix the vapour with steam with _________ at a very high temperature

Answer 7

Steam

Question 8

Cracking is a _________ _____________ reaction

Answer 8

Thermal decomposition

Question 9

What is thermal decomposition?

Answer 9

When one substance is HEATED and therefore CHEMICALLY CHANGES into at LEAST 2 new substances

Question 10

What is the catalyst used when cracking crude oil?

Answer 10

Aluminium oxide

Question 11

Most of the products of cracking are _______ and ______. Cracking would produce both of these at the end result.

Answer 11

Alkanes and alkenes

Question 12

What’s the difference between an Alkane and an Alkene?

Answer 12

An alkane is a shorter molecule structure with say 8 carbon atoms instead of 10 with single bonds - which would make it useful for petrol

An alkene is only has a small amount of carbon atoms with double bonds say with ethene it has two C atoms which is good for making plastics