Notesale: Turn your study into money

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Evolution of atmosphere
Phase 1 – volcanoes have out gas
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Surface originally molten
So hot any atmosphere ‘boiled away’
Cooled down, thin crust formed
Volcanoes still erupting
- CO2
- Water vapour
- Small amounts of other gases
Oceans form when water vapour condenses
Early atmosphere mostly CO2 , little oxygen

Phase 2 – green plants evolved and produced oxygen
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Early CO2 dissolves into oxygen
Marine organisms develop – took some oxygen
- When die buried in layers under sea, trapping CO2 in carbonate rocks
Green plants evolved
- Took CO2 out of the atmosphere
- Put back O2 by photosynthesis, oxygen levels increased

Phase 3 – ozone layer allows evolution of complex animals
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Some organisms killed due to high levels of O 2
More complex organisms evolve
Oxygen creates ozone layer, O3
- Blocks harmful rays from sun
- Enables more complex life
Very little CO2 left
1
/5 oxygen in atmosphere 20%

Human activity changing the atmosphere
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Burning fossil fuels, more common
- Releases CO2, greenhouse gases, global warming
Deforestation
- Contributes to increased CO2 levels
- Trees take in CO2, less trees = more CO2 left
Livestock farming
- Methane gas released, CH4

Volcanic activity changing the environment
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Sulfur dioxide, SO4
- Reacts with sunlight, water, oxygen and dust – volcanic smog
Carbon dioxide, CO2

Sedimentary rock
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Layers of sediment in lakes and seas
Weight presses them down, squeezing out water
Mineral cement, fluids flowing through pores
- Limestone
- Chalk
Contains fossils, rock not formed under high temperatures so imprints of fossils not destroyed

Metamorphic rock
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Heat and pressure on sedimentary rock over a long time
Mineral structure and texture changed
Chemical composition the same
- Marble, formed from limestone + chalk
- High temperatures break down limestone reforms as small crystals
- More even texture
- Harder

Igneous rock
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Molten magma pushes into the crust, cools and solidifies
Contains various minerals
Randomly arranged interlocking crystals

EXTRUSIVE IGNEOUS ROCK
Cools quickly
Above ground
Forms small crystals
E
...
rhyolite, basalt

Limestone, sedimentary, calcium carbonate, CaCO3
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Grey/white colour
Formed from sea shells
Quarried out of the ground
Used as a building material, cathedrals, statues
Virtually insoluble in water
- But acid rain dissolves it
Used for
- Road surfacing, crushed into chippings
- Cement, heated with powder and clay
- Concrete, mix cement with sand, water + gravel

Lime stone thermally decomposes, makes calcium oxide and carbon
dioxide
CaCO3  CaO +CO2
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Calcium hydroxide
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NEGATIVE EFFECTS OF QUARRYING
- Eyesore
- Noise + dust
- Destroys habitats
- Transport, more noise and pollution
- Large tips for waste materials
POSITIVE EFFECTS OF QUARRYING
- New infrastructure built + improvements
- Chemicals from limestone, dyes, paints,
medicines
- Neutralises soil, lakes from acid rain,
sulfur dioxide in power station chimneys
- Provides jobs
- Landscaping and restoration part of
quarrying contract

Most carbonates decompose in the same way
- Heat the carbonate in a boiling tube
- Pipe gas into boiling tube filled with limewater, Ca(OH) 2
- CO2 turn limewater cloudy
Less stable carbonates decompose faster, turn limewater cloudy quicker

Calcium oxide reacts with water to produce calcium hydroxide, limewater
CaO + H2O  Ca(OH)2

Alkali
Neutralise
Dissolves in water, makes limewater

INTRUSIVE IGNEOUS ROCK
Cools slowly
Underground
Forms big crystals
E
...
granite, gabbro

Reactions of acids
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Metal oxides and metal hydroxides are bases
Acid + metal oxide  salt + water
Acid + metal hydroxide  salt + water
Acid + metal carbonate  salt + water + carbon dioxide

Electrolysis, the breaking down of a compound using electricity
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D
...
1% carbon)
High carbon steel (1
...

Vaporised fractions rise up the column and are tapped off
where they condense

Complete combustion
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Enough oxygen
Harmless waste products
Clean blue flame
Lots of energy

Hydrocarbon + Oxygen Carbon Dioxide + Water (+ Energy)

Incomplete combustion
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Not enough oxygen
Poisonous + messy waste products
Smoky yellow flame
Less energy

Hydrocarbon + Oxygen  Carbon +Carbon Monoxide + Carbon Dioxide + Water (+ energy)
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Carbon monoxide gas, colourless, odourless, toxic
Carbon, soot

Choosing the best fuel
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Ease of ignition
Energy value
Ash and smoke
Storage and transport

Acid rain, sulfur let off from burning fossil fuels, mixes with oxygen in air to make sulfur dioxide
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Causes water ways to be acidic, plants and animals die
Kills trees
Damages limestone buildings
Sulfur can be removed from fuel before burnt
- Takes more energy to remove, burning more fuel for the energy
Power stations have acid scrubbers, remove harmful gases
Cars fitted with catalytic converters, clean exhaust gases

Carbon dioxide, greenhouse gas
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Acts as an insulating layer for the atmosphere
Absorbs most of the heat radiating from the sun + directs towards earth
Earth is heating up, human activity
- Deforestation
- CO2 released when trees burnt/ cut down
- Microorganism release CO2 when feeding off decaying trees
- Less CO2 removed from atmosphere
- Restoring the balance

Iron seeding
- Iron needed by plants for photosynthesis
- Injecting iron into upper oceans promote the growth
of phytoplankton
- Phytoplankton absorb CO2 , help the balance
- Some are toxic though, creates dead zones in the sea
– nothing can live there

Convert carbon dioxide into hydrocarbon
- Researching the converting of waste CO2 into
hydrocarbons
- Different methods being used, high pressure, high
temperature, metal catalyst
- Short hydrocarbons easy to produce but long ones
not
- Would be beneficial but only if green source is used
for the energy

Biogas, microorganisms decompose waste into it
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Burned to heat water, central heating
Power a turbine to generate electricity
Fuel for cars and buses
Renewable, plants that are decomposed can be replaced
Plants for biogas would have removed CO2 before used
- Balances out the CO2 released from using it
Fairly clean doesn’t produce much bi-products
Raw materials for biogas, cheap and readily available

Alcohol made from sugar
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Ethanol, used a fuel, when burns only gives off water and CO2
- Produced by using yeast to ferment sugars, sugar cane and sugar beet
- Gasohol, 10% ethanol + 90% petrol
- Lots of land used to grow crops for ethanol, less land for food growth
- Instead of pure petrol means less crude oil
- Crops needed for ethanol absorb CO2 from the atmosphere

Fuel cell, an electrical cell that’s supplied with a fuel and oxygen and uses energy from the reaction between them to generate
electricity
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Hydrogen + Oxygen  Water
Reaction creates lots of energy
Can use this for clean energy
Developed in 1960’s for space program – more practical than solar cells, safer than nuclear
Doesn’t run out or need recharging

Advantages
- More efficient than power stations or batteries
- Electricity generated directly from it (no turbines or
generators)
- Not a lot of stages, less room for energy loss as heat
- No moving parts, no energy lost through friction
- No pollutants produced, or smelly petrol cars and lorries

Disadvantages
- Hydrogen is a gas so takes more room to store
than liquid fuel
- Very explosive gas
- Hydrogen fuel is made of hydrocarbons or be
electrolysis of water, these both uses electricity

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