Fuels Flashcards
How is crude oil formed?
- Sea creatures living millions of years ago
- Fish die and their bodies fall to the bottom of the ocean
- Pressure from water pushes them further down and together
- Fossils of fish turn into crude oil
What are hydrocarbons?
Hydrocarbons are molecules that only contain hydrogen and carbon atoms
What is crude oil?
Crude oil is a thick, black, viscous liquid that floats on water. It is composed of a very large mixture of hydrocarbons.
What is the process of fractional distillation?
Crude oil is heated up until it turns into a gas. The gases enter a fractionating column, and the liquid part, bitumen, is drained off.
The column is hot at the bottom and gets cooler as you go up.
The hydrocarbons in crude oil have different boiling points, so they all condense and drain out at different places.
You end up with the crude oil separated into different fractions.
What is the order of the hydrocarbons in crude oil in terms of boiling point and what are their uses?
Gases - heating and cooking
Petrol - motor fuel
Kerosene (paraffin) - jet fuel
Diesel oil - fuel in cars and larger vehicles
Fuel oil - fuel for large ships and some power stations
Bitumen - road and roof surfacing
The longer the carbon chain in a hydrocarbon the…
- Higher the boiling point
- Less volatile it is
- More viscous it is
- Less flammable it is
What is an alkane?
An alkane is a hydrocarbon with only single carbon bonds. It has the general fomula CnH2n+2. The names of different alkanes all end in -ane. They are saturated, which means there are only single bonds.
What does saturated mean?
There are only single bonds, which means they cannot open up and make more bonds.
What is the order of alkanes and alkenes?
Methane, ethane, propane, butane, pentane, hexane
N/a, ethene, propene, butene, pentene, hexene
What is a homologous series?
A group of chemicals with the same general formula and similar chemical structures and reactions/ chemical properties
What is an alkene?
An alkene is a hydrocarbon with a carbon-carbon double bond. It has the general formula CnH2n. The names of different alkenes all end in -ene. They are unsaturated, which means the double bond can open up, allowing the two carbon atoms to bond with other atoms.
What is the test for alkenes/ alkanes?
Add bromine water to the alkane or alkene. Bromene water is orange, while alkanes/ alkenes are colourless. Alkanes will not change the colour of the water, while alkenes will make it colourless.
How is acid rain formed?
- Fossil fuels (coal and oil) are burned. Sulphur dioxide is released.
- In cars nitrogen oxides are formed and released.
- The gases react with sunlight and ozone and form sulphuric acid and nitric acid.
- The acids dissolve in the moisture in the atmosphere.
- They fall down with rain.
What are problems of acid rain?
They can contaminate soil by making it too acidic, contaminate water by aluminium, which is activated by acid rain, slow down growth and kill plants and trees and damage buildings.
How can we reduce acid rain?
Use less energy
Use more nuclear or renewable energy
Burn coal that contains less sulphur
Construct taller chimneys