Notesale: Turn your study into money

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Atoms and Elements
The nucleus
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Middle of atom
Contains protons and neutrons
Protons positively charged
Neutrons no charge
Nucleus is positively charged

The electrons
 Move around the nucleus
 Negatively charged
 Occupy shells around the nucleus

No
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of electrons
 Atoms have no charge overall
 If some electrons are added or removed the atom becomes charged and
is an ion

Elements consist of one type of atom only
 No
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g
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g
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mortar is cement mixed with sand and water
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Give an example of environmental damage caused by quarrying
habitats are destroyed
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As tech improves it becomes possible to extract more
metal so it might become economically worthwhile extracting

Extracted by reduction or electrolysis
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The Reactivity series
A metal can be extracted from its ore by reduction using carbon
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more expensive than reduction with carbon because of energy used
Copper is purified by electrolysis
 Copper ore heated in furnace
 This copper is impure – doesn’t conduct electricity, no good for wires
 Electrolysis is used to produce pure copper – good conductor

Electrolysis – breaking down of a substance using electricity
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Requires a liquid to conduct called the electrolyte
Electrolytes are often metal salt solutions made from the ore
Electrolyte has free ions which allow conduction to occur
Electrons are taken away by + electrode and given away by the -ve
electrode
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 Pure copper atoms bond to negative electrode

Extraction of Metals
Displacement reaction used to extract copper
 More reactive metals react more vigorously than less reactive metals
 Scrap iron used to displace copper from a solution
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The bacteria get
energy from the bond between copper and sulphur
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Plants can’t use copper so it
builds up in leaves plants then dried and burned and copper is collected
from the ash
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 Fossil fuels contribute to global dimming climate change and acid rain
 Fossil fuels are running out as finite amount on earth
 Recycling saves money
 Recycling cuts down on amount of rubbish sent to landfill sites which
take up land and pollute the area
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Plants take up copper and can’t use it so
it builds up in leaves
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Properties of Metals
Strong and bendy and great conductors
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Strong, bent into shape
Conduct heat well
Conduct electricity well
Useful for bridges and car bodies, saucepan bases, electrical wires

Although metals corrode when exposed to air and water so metal needs to be
protected
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Metals can get tired with stresses and
strains called metal fatigue
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Metals exact properties decide how it is best used
 Copper good conductor – wires – doesn’t react with water
 Aluminium corrosion resistant and has low density
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Many metals today are alloys
Bronze = copper + tin
used for medals and statues
Cupronickel = copper + nickel
hard and corrosion resistant used to make silver coins
Gold alloys used to make jewellery
pure gold too soft zinc copper or silver alloyed
Aluminium alloys used to make aircraft
low density alloyed with small amounts of other metals to make it stronger

Warm up Questions
Give three useful properties of most metals
strong bendy good conductors of electricity
Where are the transition metals found in the periodic table?
you can find the transition metals in the middle of the periodic table
What is the problem with iron from the blast furnace?
it is too brittle
What is an alloy?
an alloy is a mixture of metals
Which are harder pure metals or alloys
alloys because they disrupt the regular arrangement of atoms which makes it
harder for the layers to slide over each other so it is harder

Fractional distillation of crude oil
Crude oil is a mixture of hydrocarbons
 Mixture is two or more elements that aren’t chemically bonded to one
another
 Hydrocarbons made from hydrogen and carbon only
 No chemical bonds between parts of the mixture so they keep their
original properties
Crude oil split into separate groups of hydrocarbons
The fractionating column works continuously
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Vaporised crude oil rises up the column and various fractions are
constantly tapped of at different levels where they condense at
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Longer chain molecules come out
at the bottom
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Alkanes made up of chains of carbon atoms surrounded by hydrogen atoms
different alkanes have different chain lengths
Methane

ethane

Propane

Butane

Shorter the chain: the runnier less viscous, more volatile lower boiling point,
abler to ignite
The uses of hydrocarbons depend on properties
e
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gloopy hydrocarbons used for lubrication
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Petrol runny and higher boiling point – can flow into engine
and easily vaporised
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g
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Reduce acid rain by reducing sulfur emissions

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Sulfur can be removed before combustion
Expensive
Takes more energy
Power stations have gas scrubbers to take harmful gases out
Another way to reduce acid rain is to reduce usage of fossil fuels
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Because of particles of soot and
ash are produced by fossil fuels and these particles reflect sunlight back into
space or they can produce more clouds

Alternative fuels being developed
Ethanol- plant material fermented
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Carbon neutral only over product is water
Engines need to be converted
Isn’t widely available
Farmers switching from growing crops could cause increased food prices

Biodiesel- produced from vegetable oils
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Carbon neutral
Engines don’t need to be converted
Produces much less sulfur dioxide and particulates
Can’t make enough to replace diesel
Expensive could increase food prices

Hydrogen gas- electrolysis of water
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Very clean
Special expensive engine and hydrogen isn’t widely available
Still need to use energy from another source
Hard to store because it is explosive

Warm up Questions
What does a mixture consist of?
a mixture is two or more elements or compounds not chemically bonded
together
What are hydrocarbons make from?
hydrogen and carbon atoms only
Name the first three alkanes
methane, ethane, propane
List three modern day activities that depend on crude oil and its fractions
driving, electricity generation, making plastics

Cracking Crude Oil
Splitting up long chain hydrocarbons
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Long chain hydrocarbons aren’t very useful
Longer chains produced by fractional distillation are cracked
Products of cracking useful as fuels
Cracking also produces Ethene which is needed to make plastics

Cracking is splitting up long chain hydrocarbons by passing vaporised long
chain hydrocarbons over a hot catalyst at about 400-700 degrees Celsius
Catalyst is aluminium oxide
Long chain molecules crack on the surface of the powdered catalyst
Long chain hydrocarbon  shorter alkane molecule + Alkene

Alkenes
Alkenes are hydrocarbons that have a double carbon bond
 Known as unsaturated because they can make more bonds as double
bond can open up allowing two carbon atoms to bond with other atoms
 Alkenes have twice as many hydrogens than carbons
Ethene:

Propene:

Alkenes turn bromine water colourless
 Test for alkenes by adding substance to bromine water
 Alkene decolourises bromine water turning it from orange to colourless
 Because the double bond has opened up and formed bonds with the
bromine

Ethanol
Ethene can be hydrated with steam in the presence of a catalyst to make
ethanol
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Using Alkenes to make Polymers
Polymerisation
 Joining together lots of small chain alkene molecules called monomers
to form large chain molecules called polymers
 Ethene molecules joined up to form polyethene
 Propene molecules joined up form polypropene
Different polymers have different physical properties
 Depend on what it is made from and the temperature and pressure of
polymerisation
 Higher temperatures and pressure make flexible low density
 Lower temperatures and pressures with a catalyst make rigid and dense
Polymers suitable for various different uses
 Light stretchy polymers used to make plastic bags, elastic polymer fibres
used to make lycra
 Waterproof coatings, dental polymers, hydrogel wound dressings
 Biodegradable packaging
 Smart materials e
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memory foam remembers moulded shape
Polymers are cheap but don’t rot and are hard to rid
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Most polymers aren’t biodegradable don’t rot
Can’t get rid best thing to do is re use them and re cycle them
Things made from polymers are cheaper then metal products
As crude oil runs out prices will increase

Warm up Questions
What sort of hydrocarbon molecules are cracked and why are they cracked?
long hydrocarbon molecules are cracked so they can be turned into smaller
more useful hydrocarbons
Describe the conditions used for cracking hydrocarbons
high temperatures with a catalyst
Why are alkenes described as unsaturated hydrocarbons?
because they contain a double carbon bond which can be opened up to form
more bonds
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These oils can be extracted for food
and fuel
 Plant material is crushed and pressed between two metal plates
 Oil separated from crushed plant material by centrifuge or solvents
 Distillation refines oil and removes water solvents and impurities
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 Hydrophobic – attracted to oil
 Hydrophilic – attracted to water

When you shake oil and water with emulsifier the oil forms
droplets surrounded by a coating of emulsifier
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g
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The Earths Structure
crust is very thin 5-50km thick
below is the mantle has all the properties of a solid except it flows very slowly
in mantle radioactive decay takes place which creates heat which causes
convection currents
centre is the core which is made from iron and nickel

Earth’s surface made from tectonic plates
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crust cracked into large pieces called tectonic plates
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plants and algae evolved in the carbon dioxide atmosphere
G
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Oxygen and argon come out together so another column is used to
separate them
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because he wasn’t a geologist and couldn’t explain how the plates drifted
State one geological feature often seen at the boundary of two tectonic plates
volcanoes
Where did the gases in the early atmosphere come from?
volcanoes
What is the process used to separate gases in the air?
fractional distillation

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