DF 5 Flashcards
What is cracking?
The breaking down of long-chained saturated hydrocarbons into a mixture of shorter-chained hydrocarbons
How do we separate different products of cracking?
Fractionating column via fractional distillation
How is cracking done?
By heating heavy oils in the presence of a catalyst
What are the products of cracking alkanes?
Branched alkanes + branched alkenes
OR
Smaller alkanes + cycloalkanes
What are the products of cracking cycloalkanes?
Alkenes + branched alkene
What are the products of cracking alkenes?
Smaller alkenes
What catalyst are used for cracking?
Aluminium oxide or silicon oxide
What conditions are used for cracking in industry?
Zeolite catalyst and 450 degrees celcius
What is a catalyst?
A substance which speeds up the rate of reaction but can be recovered chemically unchanged at the end
And does not get used up
What is catalysis?
The process of speeding up a chemical reaction using a catalysr
What is the method for cracking?
1) pipette 2cm^3 of liquid paraffin so that it soaks into the mineral wool
2) Remove any excess paraffin with a pipette
3) Clamp the boiling tube near the neck and place the catalyst in the middle of the tube
4) Attach the bung with the delivery tube into a trough of water
5)Use a roaring blue flame to heat the catalyst 10 seconds for every second you heat the paraffin
How to test for a short-chain alkane?
Should smell of camping gas or light to prove it is flammable
How to test for an alkene?
- Add bromine water
- SHAKE
- Orange -> colourless
