Cracking and Alkenes

Why do we use cracking?

Because long chain hydrocarbons aren’t flammable and therefore do not make good fuels, therefore we need to break them down

As well as short chain hydrocarbons, what else is made as a product of cracking?

An alkene

What are the two types of cracking?

• Catalytic cracking

• Steam cracking

What is used in catalytic cracking?

A high temperature and a catalyst to speed up the reaction

What is used in steam cracking?

A high temperature and steam

The alkene functional group is…

A double bond between two carbon atoms

Alkenes are useful for…

Making polymers and as the starting material for other chemicals

Alkenes are __ reactive than alkanes

More

How can we test for alkenes?

By shaking the sample with bromine water, which is orange

What colour will the solution go if an alkene is present?

Colourless

What is the general formula for alkenes?

CnH2n

Aka. We can figure out the amount of hydrogen atoms by multiplying the amount of carbon atoms by 2

What are the 4 main alkenes?

• Ethene

• Propene

• Butene

• Pentene

Are alkenes saturated or unsaturated?

Unsaturated

Why are alkenes called unsaturated?

Because they have a carbon double bond and therefore have fewer hydrogen atoms than their corresponding alkane