C 7 Obtaining useful substances from crude oil Flashcards
(10 cards)
What is cracking?
A process that breaks down long-chain hydrocarbons into shorter, more useful hydrocarbons.
Why is cracking important?
It helps match supply with demand by producing more short-chain hydrocarbons for fuel and alkenes for making plastics.
What are the conditions needed for cracking?
Cracking requires high temperature and a catalyst (catalytic cracking), or high temperature and pressure (thermal cracking).
What are the products of cracking?
Short-chain alkanes and alkenes.
What is the test for alkenes?
Add bromine water – it turns colourless if an alkene is present.
What is polymerisation?
A chemical reaction where alkenes join together to form long-chain polymers.
What type of bond do alkenes contain?
A carbon–carbon double bond (C=C).
What is the general formula for alkenes?
CnH₂n.
What is an example of a polymer made from ethene?
Poly(ethene) – used for plastic bags and bottles.
Why are polymers useful?
Polymers are lightweight, durable, and can be moulded into different shapes for many uses.
