Chemistry C1

Atoms
1. Element - A substance made of only one atom
2. Proton - Positively charged sub-atomic particle (same number of electrons)
3. Neutron - Neutrally charged sub-atomic particle (Mass-atomic no.)
4. Electron - Negatively charged sub-atomic particle (same number of protons)
5. Group number shows number of electrons in outer shell
6. Atoms with same number of electrons in the outer shell have similar chemical properties
7. Bonds
  1. Ionic - When a atom loses or gains an electron
  2. Covalent - When atoms share electrons
8. Equations
  1. Reactants - The substances which react together
  2. Products - The substances made
  3. Symbol equations e.g. C+O = CO2
Limestone
1. Uses
  1. Raw material for concrete, cement and mortar
  2. As pavements
  3. For the base of roads and railways
2. Quarrying
  1. Advantages
    1. Creates jobs for locals
    2. Boosts local economy with increased income
  2. Disadvantages
    1. Reduced tourism
    2. Increased traffic
    3. Noise, visual and air pollution
    4. Destruction of natural wildlife
3. Heat with clay to make CEMENT
  1. Mix with sand to make MORTAR
  2. Mix with sand and aggregate to make CONCRETE
Extracting Metals
1. Ore - A rock which contains enough of a metal to make it economical to extract
2. Native - Unreactive metals found in nature e.g. Gold
3. Reduction - Removal of oxygen from a compund
4. Oxidisation - A reaction between an element and oxygen to form an oxide
5. Electrolysis
6. Phytomining
  1. Plants grow and absorb ions through roots.
    1. Plants are burnt to produce ash.
      1. Ash is dissolved in sulfuric acid
        Solution is electrolyed
7. Bioleaching
  1. Bacteria feed on low grade ore
    1. Through biological and chemical processes we get a solution called a leachate
      1. Scrap iron and electrolysis are then used
8. Reduction
  1. The ore is oxidised by being smelted in air
    1. The oxide is smelted with carbon to produce CO2 and pure metal
9. Recycling
  1. Advantages
    1. Metal ores last longer
    2. Less energy to recycle than extract metal
    3. Fewer mines needed
    4. Less polution
  2. Disadvantages
    1. Used items must be transported to recycling centre
    2. Metals be sorted
    3. Saves different amounts of energy depending on the metal
10. Alloys
  1. Mixtures of metals
  2. Steel is a mixture of iron carbon and other metals it is stronger than regular iron
11. Low density and resistant to corrosion
  1. Aluminium e.g. jet parts
  2. Titanium e.g. hip joints
12. Transition Metal
  1. Good conductors
  2. Useful as structural materials
  3. Can be bent or hammered into shape
Fuels
1. Alkanes - are saturated and only have single bonds e.g. Methane
  1. General formula is CnH2n+2
2. Alkenes - are unsaturated and have double carbon-carbon bonds
  1. General formula is CnH2n
3. Fractional Distillation
  1. Used to seperate mixtures containing several different substances e.g. crude oil
  2. The oil is heated to boiling point (evaporated)
    1. The vapour rises up the column
      1. Each fraction condenses at different points because each alkane has a different boiling point (based on the number of bonds it contains)
4. Compounds consisting of chains of hydrogen and carbon only
5. Combustion
  1. Complete combustion - The hydrogen and carbon react with oxygen to form carbon dioxide and water vapour
  2. Partial combustion - When there is not enough oxygen so carbon monoxide and particulates form
  3. Sulfur dioxide - Contained in most fossil fuels and creates acid rain which damages limestone
  4. Particulates - They reflect sun back and cause global dimming
6. Biofuels
  1. Advantages
    1. Renewable
    2. Carbon neutral
    3. Biodiesel can be used in diesel engines
    4. Bioethanol can be mixed with petrol and used in petrol engines
  2. Disadvantages
    1. Farmland is used for biofuel production rather than food
    2. Non-renewable sources may be used indirectly e.g. for transport
    3. Are more expensive to produce than fossil fuels
  3. Hydrogen
    1. No CO2 produced when burned
    2. Fossil fuels may be used to create it
    3. It is hard to store
  4. Ethanol
    1. Fermentation
      1. A natural process which requires yeast
    2. Hydration of ethene
      1. An industrial process which requires steam (in the presence of a catalyst)
      2. Ethene is made from crude oil
Polymers
1. Cracking
  1. A thermal decomposition reaction in which hydrocarbons are broken down to form smaller hydrocarbons as they are more useful
  2. The vapours are either passed over a hot catalyst or mixed with steam and heated to very high temperatures
2. Formation
  1. Alkenes are used to make polymers (plastics)
  2. Alkenes join together to form monomers
  3. They join in a polymerisation reaction to form large molecules called polymers
  4. e.g. Ethene - Poly(ethene)
3. Uses
  1. Hydrogels (Absorb water) for nappies
  2. False teeth and fillings
4. Landfill
  1. Advantages
    1. Waste is quickly disposed of
    2. Waste is out of view
  2. Disadvantages
    1. Space is limited
    2. Polymers are not biodegradable
    3. Landfills are unattractive and attract animals
Plant oil
1. Extraction
  1. Pressing & Filtering
    1. The plant material is crushed to release oil and water
    2. The oil floats on top so can be filtered off
  2. Steam Distillation
    1. Water is boiled into steam
      1. Steam passes through the plants
        The steam carries the oil
        The mixture of steam/oil is condensed
        The oil floats on top of the water
2. Cooking with oil
  1. Advantages
    1. Cooks at higher temperatures
    2. Cooks faster than when in water
    3. Has different flavouring
  2. Disadvantages
    1. Releases more energy (calories) when eaten
3. Emulsions
  1. Oils do not dissolve in water but a mixture is called an emulsion
  2. Advantages of emulsions
    1. They are thicker
    2. They have better food coating ability
    3. Have a better texture/appearance
  3. Emulsifiers
    1. Substance which makes emulsions stable by preventing them from seperating out
4. Saturation
  1. Saturated vegetable oils only have C-C single bonds
  2. Unsaturated vegetable oils have some C=C double bonds
  3. Polyunsaturated oils have lots of C=C double bonds
  4. Unsaturated oils are better for your health
  5. Testing
    1. Bromine water turns colourless when mixed with an unsaturated substance
  6. Hydrogenation
    1. Requires hydrogen, a nickel catalyst and 60°C
    2. The process by which unsaturated oils are hardened by breaking the C=C bonds
    3. Hydrogenated oils have higher melting points so they are:
      1. Solid at room temperature
      2. Used to make margarine etc
Early Earth
1. Structure
  1. Crust - Outer layer 35km & solid
  2. Mantle - Middle layer 3000km & flowing solid
  3. Outer core - Inner layer 5200km & liquid
  4. Inner core - Innermost layer 6400km & solid
2. Tectonic Plates
  1. The earth's crust is cracked into several pieces
  2. Convection currents
    1. They move the tectonic plates from within the mantle
    2. They are generated by radioactive decay processes within the Earth
  3. Continental Drift
    1. Discovered by Alfred Wegener a German Scientist
    2. Continents used to be a supercontinent called pangea
    3. Evidence
      1. Coasts lines have similar interlocking shapes
      2. Fossils of land mammals are the same
3. Early Atmosphere
  1. Main gases
    1. Nitrogen 78%
    2. Oxygen 21%
    3. Other gases 1% e.g. argon and carbon dioxide
  2. Air as a raw material
    1. They can be separated by fractional distillation
    2. Air is cooled to -200°C (into a liquid)
      1. At -79°C CO2 and O2 are removed
        It is piped into a fractioning column
        Nitrogen gas leaves out the top
        Liquid oxygen leaves out the bottom
  3. Miller-Urey Experiment
    1. Primordial Soup
      1. Water vapour, ammonia, methane and hydrogen
      2. It formed amino acids (The building blocks of life)
  4. Carbon Cycle

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	Created by miles.a.moran over 9 years ago