Topic 5 - Fuels Flashcards
What is crude oil ?
A mixture of different sized hydrocarbon molecules
What are hydrocarbons ?
Fuells such as petrol and diesel
There made of just carbon and hydrogen
Why is crude oil able to condense at different points ?
The different molecules aren’t chemically bonded so they keep their original porperties.
How is crude oil split into seperate groups of hydrocarbons ?
Fractional distillation
How does a fractional distillation column work ?
Works continously with heated crude oil piped in at the bottom
Vapourised oil rises up the column and the various fractions are constantly tapped off at different levels where they condense
As you go up the column what ahppens to the molecules of the hydrocarbons ?
- They become shorter
- More flammable
- Moer runny - less viscous
As you go down the column what happens to the molecules ?
- become longer
- Higher boiling point
- not very volatile
- does not flow easily
- does not inite easily
What are the seven seperate groups that are made fromsplitting hydrocarbons using fractional distillation ?
(From the top)
- Gases
- Petrol
- Naptha
- Kerosene
- Diesel
- Fuel Oil
- Bitumen
What is complete combustion ?
When fuel burns in plentiful oxygen (witha blue flame) to form carbon dioxide and water
What is the equation for complete combustion of methane ?
CH4 + 2O2 > 2H2O+ CO2
What is incomplete combustion ?
- When a fuel burns in a limited supply of oxygen (with a yellow flame) the products from this reaction are:
- Carbon + carbon monoxide + carbon dioxide + water
What are the properties of carbon monoxide ?
- Odourless
- Colourless
- Toxic gas
- Reduces maount of oxygen in the blood
What is the symbol equation for incomplete combustion of methane ?
4CH4 + 6O2 > C + 2CO2 + CO2 + 8H2O
What 4 things do you need to consider when choosing the best fuel ?
- Ease of ignition - burns easily
- Energ value - amount fo energy released
- Ash and smoke - how much ash is left behind
- Storage and trasnport - special canisters and transported carfeully
