Fuels Flashcards
What is crude oil
Crude oils is a mixture of hydrocarbons it can be split up by fractional distillation
What are hydro carbons
Fuels made of just carbon and hydrogen
What happens in the fractional distillation column
Crude oil is piped in at the bottom
It is heated and the vaporised oil rises up and then the different substances are piped of at the different levels where they condense
The shorter the molecules the more flammable the hydrocarbon
The shorter the molecule the more viscous
What is the order of the fractional distillation column from bottom to top
Bitumen Big Fuel oil Females Diesel Don't Kerosene Kill Naphtha Normal Petrol People Gases Generally
Describe bitumen
Used to surface roads and roofs
40 carbon atoms in the molecule
Describe fuel oil
Used as fuel for ships and in some power stations
Condenses at 340 degrees
35 carbon atoms in the molecule
Describe diesel
Used as fuel for lorries trains and in some cars
Condenses are 250degrees
20 carbon atoms in the molecule
Describe kerosene
Used as and aircraft fuel
180degrees condensing point
15 carbon atoms in the molecule
Describe naphtha
Used as lighter fluid and in the chemical industry
10 carbon atoms in molecules
Describe petrol
Used for cars
8 carbon atoms per molecule
110degrees condensing point
Describe gases
Used for cooking and heating
3 carbon atoms per molecule
What is complete combustion
Hydrocarbon+oxygen->carbon dioxide + water
Hydrogen and carbon have been oxidised
Describe complete combustion
Releases lots of energy and only produces harmless waste products
gas burns with a clean blue flame
What is incomplete combustion
Hydrocarbon + oxygen -> carbon+carbon dioxide+carbon monoxide+ water
There isn’t enough oxygen
Describe incomplete combustion
It produces carbon monoxide which is a colourless odourless toxic gas which replaces the oxygen in the hemaglobyn
There is less energy and a smoky yellow flame
What makes the best fuel
Easily ignightable
High energy value
Little waste like ash and smoke
Easily stored and transported
What are the problems with burning fuels
Burned in power stations and cars
Carbon dioxide is released into the atmosphere
Sulfur dioxide is also put into the air
If there is not enough oxygen the soot and carbon monoxide are also released
How does sulfur dioxide cause acid rain
When sulfur dioxide mixes with the clouds it forms dilute sulphuric acid this then falls as acid rain
What are the negatives of acid rain
Causes lakes to become acidic
Kills trees and damages limestone buildings
How is acid rain prevented
Sulfur can be removed from the fuels before they are burned but it costs more and uses more energy
Power stations use limestone which reacts with the sulfur dioxide and neutralises it
Catalytic converters are used in cars to clean up the emissions
What is global warming
The temp of the earth is a balance between the heat revived form the sun and the heat radiated back into space
The ozone layer act like an insulator so when the sun rays come into the atmosphere then reflect of of the Artus surface they trap some heat to keep us warm but as greenhouse gases increase they absorb more of the heat and re radiate it back to the earth so our earth gradually is heating up
How does human activity effect carbon dioxide levels
Deforestation
carbon dioxide is released when the trees are burned
Micro organisms feed on the decaying wood and release co2 from respiration
Living trees do photosynthesis so if there are less trees then less co2 is removed form the atmosphere
Burning fossil fuels
What is iron seeding
Injecting iron into the upper oceans promotes the growth of plankton which takes co2 from the atmosphere
But there is no way of controlling the growth and some plankton are toxic and some micro organisms which decompose dead plankton use up oxygen creating dead zones in the sea
Describe the making bio gas
Micro organisms are used to decompose living organisms water or dead plants to create biogas
What is bio gas used for
Burned to heat water
Power turbines to generate electricity
Fuel for cars and buses
What are the advantages of bio gas
It is renewable
The dead plants used to make bio gas used carbon dioxide when alive so this is only released when they are burned making the process carbon neutral
It is a clean fuel
The materials used are cheap and readily available
How is ethanol produced
By using yeast to ferment sugars such as sugar cane or sugar beet
Cars can be adapted to run on semi ethanol fuels
What are the disadvantages of ethanol production
Large amounts of land are needed to grow the product so less land can be used for the people of the country to grow food
What are the advantages of ethanol
Using gasohol instead of pure ethanol means less crude oil is being used
The production of ethanol is carbon neutral but distilling the ethanol does Theke energy which releases some carbon dioxide
What is a fuel cell
A fuel cell is an electrical cell that uses a fuel and oxygen and a reaction between them to generate electricity
It will keep producing energy as long as the fuel is restored
What are the advantages of hydrogen oxygen fuel cells
They are much more efficient that power stations of batteries
The energy comes directly from the reaction so there are fewer places for the energy to be lost
There are no moving parts so energy isn’t lost through friction
There is no pollution
What are the disadvantages of hydrogen oxygen fuel cells
Hydrogen is a gas so it takes up lots more space than liquid fuels
Hydrogen is very explosive so it wouldn’t really be safe
The hydrogen fuel often comes from hydrocarbons or electrolysis which takes energy
Mass of fuel burned =
Initial mass of fuel and burner - final mass of fuel and burner
Describe alkanes
They have single bonds between the chains of carbon
They are saturated hydrocarbons
They don’t turn bromine water colourless because they have no spare bonds
They don’t form polymers
Describe alkenes
They are chains of carbon atoms with one ore more double bond
They are unsaturated hydrocarbons
They de colourise bromine water because they have spare bonds left
Describe cracking of hydrocarbons
Long chain hydrocarbons aren’t useful so cracking breaks up the chains to make them more useful
For cracking to concur you need heat and a catalyst
The process make a shorter alkane molecule and alkenes
What up are the properties of poly Ethene
Stretchy and light often used in plastic bags
What are the properties of polypropene
It is tough but flexible so used for plastic containers or thermal under wear
Describe polychloreothene
It is flexible and resistant to wear so used for lots of things like clothing electric cables and wires
Why are plastics bad
They are non biodegradable so they will stay in landfill for a long time
When burned they can give off toxic gases
It is expensive and time consuming to separate plastics for recycling
