C7.4 Cracking

Why are longer hydrocarbon molecules cracked into smaller ones?

• They burn more easily and are in higher demand

• They are more stable and form more soot

• They produce more carbon monoxide

What is the name of the process used to break large hydrocarbons into smaller ones?

• Distillation

• Polymerisation

• Cracking

Which type of reaction is cracking an example of?

• Addition

• Thermal decomposition

• Neutralisation

What is always required for cracking to take place?

• A low temperature and a vacuum

• A high temperature and a catalyst or steam

• UV light and cold water

In one method of cracking, what is passed over a hot catalyst?

• Crude oil

• Vaporised hydrocarbons

• Solid paraffin

Which type of bond do alkenes contain that alkanes do not?

• Ionic bond

• Triple bond

• Double carbon-carbon bond

What is a positive test for an unsaturated hydrocarbon like an alkene?

• It turns limewater cloudy

• It turns bromine water colourless

• It produces a popping sound with hydrogen

Which statement is true about alkanes?

• They are more reactive than alkenes

• They do not react with bromine water

• They have at least one double bond

Which type of molecule is useful for making polymers?

• Alkanes

• Alkenes

• Alcohols

What is pentane classified as?

• Alkene

• Polymer

• Alkane