7.1.4 - Cracking & Alkenes

What is cracking?

When large hydrocarbons are thermally broken down into smaller and useful molecules.

What type of reaction is cracking?

Thermal decomposition.

What are the conditions for cracking?

Reactant heated to vapor, passed over a hot catalyst (catalytic cracking) or heated to vapor, mixed with steam and heated to high temperatures (steam cracking).

How are the products of cracking used?

The products are alkanes and alkenes - used as polymers and starting materials for synthesis.

What is an alkene?

• Unsaturated hydrocarbon. Contains a C=C bond.

• General formula for alkenes is C_nH_2n

What is the test for alkenes?

Add bromine water. Color changes from orange to colorless.