1
Q
What are the conditions needed for cracking?
A
- high temperature
- aluminium catalyst
2
Q
Why is cracking done?
A
- to help match supply and demand
- there is a higher supply of bigger hydrocarbons in crude oil than the demand for them
- so they are cracked into smaller hydrocarbons to meet the demand for them, as the original supply was less
3
Q
What is cracking?
A
- splitting long alkane molecules into smaller alkane and alkene molecules
- thermal decomposition
4
Q
How can oil cause political problems?
A
- prices rise as stocks are used up, countries with big stops may start keeping more for themselves instead of selling
- countries with most oil and natural gas will have power over other countries. They can choose who and who not they supply to, inciting political conflict and even war
- harder for countries without lots of oil to get a hold of it, we may depend on politically unstable countries and our supply could be cut off at any time
5
Q
How can oil cause environmental problems?
A
- oil tankers crashes, oil floats on water and spreads out by the waves and tides into a big oil slick
- oil covers sea birds’ feathers, stopping them being waterproof, water soaks into feathers and they die of cold (also, birds can’t fly with oil matted wings)
- detergents used to clean oil slicks break oil into droplets and make it easier to disperse (some harm wild life, can be toxic to marine creatures like fish and shellfish)
6
Q
What needs to be considered when picking the best fuels?
A
- energy value
- availability
- storage (if flamable or explosive it needs to be stored safely)
- cost
- toxicity
- ease of use (whether is lights easily and or move it safely)
- pollution
7
Q
What is complete complete combustion?
A
- when there is plenty oxygen
- complete combustion of any hydrocarbon will produce only carbon dioxide and water
- has a blue flame
8
Q
What are the benefits of complete combustion?
A
- clean and non-poisonous
- lots of energy produced
9
Q
What is incomplete combustion?
A
- when there isn’t enough oxygen
- carbon monoxide and carbon are produced
- smoky yellow flame
10
Q
What are the disadvantages of incomplete combustion?
A
- less energy
- black carbon is sooty
- carbon monoxide is poisonous, colourless and odourless
11
Q
What is the process of cracking?
A
- vapourised hydrocarbons pass over a powdered catalyst at 400C-700C
- aluminium oxide is the catalyst
- the long chains split on the surface of bits of catalyst
12
Q
How to reduce the risk of carbon monoxide leaks?
A
-regularly service gas appliances
