Option F Fuels and Energy

By Tony Coleman,2014-11-26 17:06
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Option F Fuels and Energy

Option F : Fuels and Energy - Carolina Biasoli

The developments of human society has been directly related to the ability to use and manipulate

    fuels for energy production. This option considers the chemical principles and environmental

    issues associated with the use of fossil fuels, and nuclear and solar energy.

F.1 Energy Sources (1 h)

    F.1.1 State desirable characteristics of energy sources.

    ; Easily accessible

    ; Release energy at a reasonable rate

    ; Cheap

    ; Plentiful

    ; Not detrimental to environment

    ; Not detrimental to health

    F.1.2 Outline current and potential energy sources.

    ; Fossil fuels:

    ; Coal, oil, natural gas

    ; Non-renewable

    ; Contain carbon and hydrogen atoms

    ; Energy released when oxidized to form carbon dioxide and water

    ; Nuclear energy:

    ; Nuclear fission:

    o Large atomic nuclei split into smaller nuclei

    o Matter is converted into energy

    o Energy harnessed in nuclear power stations and converted into electricity

    o Large amounts of energy

    o Hard to control reactions

    o Problems associated with radioactive materials

    ; Nuclear fusion:

    o Potentially even more powerful

    o Combination of smaller nuclei to form larger nuclei

    o Problems in harnessing energy in a controlled way

    o No commercial use

    ; Biomass:

    ; Fuel produced by biological processes

    ; Energy from Sun through photosynthesis (6CO(g) + 6HO(l) CHO(s) + 6O(g)) 2261262

    ; Burning plant materials reverses process, releasing energy

    ; Fermentation of starch and sugars ethanol

    ; Renewable

    ; Not enough energy for demands of modern society

    ; Electrochemical cells:

    ; Difference in redox potential flow of electrons

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    ; Portable source of energy

    ; Stores limited amounts of energy

    ; Solar energy:

    ; Non-polluting

    ; Freely available during daylight hours

    ; Harnessed by solar heating panels direct storage of energy

    ; Photovoltaic cells convert solar energy into electricity ; Other energy sources:

    ; Renewable

    ; Not harnessed efficiently

    ; Wind power, wave power, hydroelectric power drive generator

    ; Tidal energy:

    o harnessed from gravitational force between Earth and Moon

    o only generated when there is tidal movement

    ; Geothermal energy:

    o Heat stored in the interior of the Earth

    o Generated by gravitational forces + natural radioactivity

    F.2 Fossil Fuels (4h)

    F.2.1 Describe the formation and characteristics of coal, oil and natural gas.

    ; Coal

    ; Formation:

    o Fossilized plant material

    o Carboniferous period

    o Pressure + Heat causes plant material peat lignite sub-bituminous

    soft coal bituminous soft coal hard coal

    o Percentage of carbon increases at each stage

    ; Characteristics:

    o Readily combustible

    o 40-98% carbon + volatile materials + moisture

    o Made up of elements H, O, N, S

    o Analysis on basis of water content, mineral impurity, volatile materials, fixed

    carbon content

    ; Petroleum/Crude Oil

    ; Formation:

    o Remains of marine organisms

    o Paleozoic period

    o Sediments built up on top of organic layers

    o High pressure + biochemical activity

    o Collected in traps

    ; Characteristics:

    o Dark, foul-smelling liquid

    o Straight-chain + branched + cyclic + aromatic hydrocarbons

    o N, O, S in small quantities

    o Liquid easy to transport

    ; Natural Gas

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    ; Formation:

    o Formed from the decomposition that produced crude oil and coal

    ; Characteristics:

    o Mainly methane (85-95%), ethane, propane, butane

    o Scarce supplies

    F.2.2 Determine and compare the enthalpies of combustion of coal, oil and natural gas.

    ; Heat evolved when one mole of a substance is completely burnt in oxygen

    ; To calculate, need:

    ; Known mass of substance being burned

    ; Temperature change of known mass of water

    ; Specific heat of water

    ; Specific heat of calorimeter

    ; Mass of calorimeter

F.2.3 Outline the composition and characteristics of the crude oil fractions used for fuel.

    Fractions Carbon Chain Length Boiling Point Range Major Uses

    Gaseous Fuels for automobiles, 0-20

    Hydrocarbons cooking, domestic + 1-4

    industrial heating (gases)

    Petroleum Ether / Solvents for varnishes, 20-100

    Naphta dry cleaning, cracking 5-7

    stock for methane (liquids)

    Gasoline Fuels for internal 40-175

    combustion engines 5-12 (readily vaporize in

    car engines)

    Jet engine and diesel Kerosene Oil

    fuel 175-300



Gas Oil / Diesel Oil Diesel fuel, cracking 300-400

    stock to produce 18-24

    gasoline (liquids)

    Lubricating Oil / Wax Lubricants, cracking

    stock Oil / Greases 20-30 Non-volatile