Cracking

What is Cracking?

Within Chemistry, which covers atoms, bonding, reactions, the periodic table, organic chemistry and the chemistry of everyday life, this topic explains Cracking. Chemistry links what you can see in the lab to the particles and bonds behind it, so each topic here shows that link in a model.

Check that you can explain Cracking in your own words and give one example from everyday life. If you can do that, you have understood the core idea.

Understanding Cracking helps you explain why substances behave as they do, from cleaning products and food to medicines.

Cracking in detail

Cracking breaks long-chain hydrocarbons into shorter, more useful ones. Catalytic cracking passes vapour over a hot catalyst such as aluminium oxide at about 550 °C, while steam cracking uses high temperatures with steam. It is a thermal decomposition.

Products are a shorter alkane and an alkene, for example C₁₀H₂₂ → C₈H₁₈ + C₂H₄. Cracking meets the demand for petrol and provides alkenes for making plastics, as there are more long-chain fractions from crude oil than are needed.

How the interactive helps you understand Cracking

Watch the reaction model in the interactive. Use any sliders or buttons it offers to change the values and see how the reaction model responds.

Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Cracking.

Real-life uses and examples

• Use Cracking to explain what happens in a lab experiment and why.
• Link Cracking to everyday products such as cleaning agents, food and medicines.
• Read a chemical equation or diagram and work out what Cracking shows.

Common mistakes to avoid

• Describing what happens without explaining the particles or bonds involved.
• Mixing up the names of substances or ions when you describe Cracking.
• Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.