Post on 08-Aug-2018
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Chemistry Unit 1
AQA
W Richards
mailto:mail@educationusingpowerpoint.org.ukmailto:mail@educationusingpowerpoint.org.uk8/22/2019 Chemistry Unit 1 (1)
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The structure of the atom
ELECTRON
negative, massnearly nothing
PROTON positive, same
mass asneutron (1)
NEUTRON neutral, same
mass asproton (1)
The Ancient Greeks used to believe that
everything was made up of very small particles. Idid some experiments in 1808 that proved thisand called these particles ATOMS:
Dalton
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Mass and atomic number
Particle Relative Mass Relative Charge
Proton 1 +1
Neutron 1 0
Electron Very small -1
MASS NUMBER = number ofprotons + number of neutrons
SYMBOL
PROTON NUMBER = number of
protons (obviously)
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Mass and atomic numberHow many protons, neutrons and electrons?
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04/08/2013Electron structure
Consider an atom of Potassium:
Potassium has 19 electrons.These electrons occupyspecific energy levelsshells
Nucleus
The inner shell has __ electrons
The next shell has __ electrons
The next shell has __ electrons
The next shell has the remaining __ electron
Electron structure
= 2,8,8,1
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04/08/2013Electron structure
Draw the electronic structure of the following atoms:
Electron structure
= 2,8,8,2
Nucleus
Electron structure
= 2,8,2
Nucleus
Electron structure
= 2,5
Nucleus
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04/08/2013Periodic Table IntroductionHow would you arrange these elements into groups?
http://localhost/var/www/apps/conversion/tmp/scratch_7/rates%20of%20reaction.exe8/22/2019 Chemistry Unit 1 (1)
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Mendeleev
Periodic table
The periodic table arranges all the elements
in groups according to their properties.
Horizontal rows are called PERIODS
Vertical
columns arecalled GROUPS
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H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
The Periodic TableFact 1: Elements in the same group have the
same number of electrons in the outer shell (thiscorresponds to their group number)
E.g. all group 1 metals
have __ electron intheir outer shell
These elements
have __ electronsin their outer shell
These elements have
__ electrons in theirouter shells
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H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
The Periodic TableFact 2: As you move down through the periods an
extra electron shell is added:
E.g. Lithium has 3electron in theconfiguration 2,1
Potassium has 19 electrons in
the configuration __,__,__,__
Sodium has 11electrons in the
configuration 2,8,1
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H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
The Periodic TableFact 3: Most of the elements are metals:
These elementsare metals
This line divides
metals from non-metals
These elements are
non-metals
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H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
The Periodic TableFact 4: (Most important) All of the elements in
the same group have similar PROPERTIES. Thisis how I thought of the periodic table in the firstplace. This is called PERIODICITY.
E.g. consider the group 1 metals. They all:
1) Are soft
2) Can be easily cut with a knife
3) React with water
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04/08/2013Group 1 The alkali metals
Li
Na
K
Rb
Cs
Fr
Watch video of thesemetals reacting with water(from Sky Ones Brainiac)
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http://www.youtube.com/watch?v=m55kgyApYrYhttp://www.youtube.com/watch?v=m55kgyApYrYhttp://www.youtube.com/watch?v=m55kgyApYrYhttp://www.youtube.com/watch?v=m55kgyApYrYhttp://www.youtube.com/watch?v=m55kgyApYrYhttp://www.youtube.com/watch?v=m55kgyApYrY8/22/2019 Chemistry Unit 1 (1)
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04/08/2013Group 0 The Noble gases
He
Ne
Ar
Kr
Xe
Rn
Questions:
1) How many electrons do these elements havein their outer shell?
2) How does this affect their reactivity?
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CompoundsCompounds are formedwhen two or moreelements arechemically combinedby sharing or giving ofelectrons. Some
examples:
Glucose
Methane
Sodiumchloride (salt)
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Some simple compounds
Methane, CH4 Water, H2O
Carbondioxide, CO2
Ethyne, C2H2sulfuric acid,
H2SO4
Key
Hydrogen
Oxygen
Carbon
sulfur
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04/08/2013Bonding introduced
Hi. My names Johnny Chlorine.Im in Group 7, so I have 7
electrons in my outer shell
Id quite like to have a full outershell. To do this I need to GAINan electron. Who can help me?
Cl
Cl
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04/08/2013Bonding
Here comes one of my friends, HarryHydrogen
Hey Johnny. Ive only got one
electron but its really close to mynucleus so I dont want to lose it.
Fancy sharing?
Cl
H
Cl H
Now were both really stable.Weve formed a covalent bond.
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04/08/2013Bonding
Here comes another friend, Sophie
Sodium
Hey Johnny. Im in Group 1 so I haveone electron in my outer shell. UnlikeHarry, this electron is far away from
the nucleus so Im quite happy to getrid of it. Do you want it?
Cl
Now weve both got full outer shellsand weve both gained a charge.
Were both called IONS and weve
formed an IONIC bond.
Na
Okay
Cl Na
+-
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B l
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04/08/2013Balancing equations
Consider the following reaction:
Na O
H HH HNa
OH
Sodium + water sodium hydroxide + hydrogen
+ +
This equation doesnt balance there are 2 hydrogenatoms on the left hand side (the reactants and 3 onthe right hand side (the products)
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B l
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04/08/2013Balancing equations
We need to balance the equation:
NaO
H H
H H
Na
OH
Sodium + water sodium hydroxide + hydrogen
+ +
Na
O
H H
Na
OH
Now the equation is balanced, and we can write it as:
2Na(s) + 2H2O(l) 2NaOH(aq) + H2(g)
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04/08/2013Some examples
Mg + O2
Zn + HCl
Fe + Cl2
NaOH + HCl
CH4 + O2
Ca + H2O
NaOH + H2SO4
CH3OH + O2
MgOZnCl2 + H2
FeCl3
NaCl + H2O
CO2 + H2O
Ca(OH)2 + H2
Na2SO4 + H2O
CO2 + H2O
22
2 3
2
2
2
2 3
2
2
2
2
2 4
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f
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04/08/2013Conservation of mass in reactions
In any reaction the total mass of products isthe same as the total mass of the reactants
Example 1Magnesium oxide and hydrochloric acid
MgO
H Cl
MgCl
Cl
H
H
OH Cl
1 x magnesium, 1 x oxygen, 2 xhydrogen and 2 x chlorine atoms
Also 1 x magnesium, 1 x oxygen, 2x hydrogen and 2 x chlorine atoms
C
H
H
H
HO
O
OO
OH H
OH H
CO
O
Example 2Burning methane
04/08/2013Li
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04/08/2013Limestone
Limestone is a rock made up of mainly calciumcarbonate. Its cheap and easy to obtain. Some
uses:
1) Building materials limestone can be ______and cut into blocks to be used in _______.However, it is badly affected by ____ ____.
2) Cement making limestone can be
roasted
in a rotary kilnto produce dry cement. Its then mixed with sand and _____to make _______.
View video of limestone being quarried
Words building, quarried, gravel, concrete, acid rain
04/08/2013Li
http://www.youtube.com/watch?v=VlLKQncIl6Ehttp://www.youtube.com/watch?v=VlLKQncIl6E8/22/2019 Chemistry Unit 1 (1)
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04/08/2013Limestone
If soil is too _____ crops will fail. Limestone can also be usedas a neutralising agent. There are two reactions to know:
1) Firstly, a THERMAL _________________ reaction is usedto break the calcium carbonate down into calcium oxide and
_______ __________:
2) This is then slaked with water to produce calciumhydroxide:
Calcium hydroxide is alkaline and is used to ______ acidic soil.
Calcium carbonate calcium oxide + carbon dioxideHEAT
Calcium oxide calcium hydroxideWATER
Words acidic, neutralise, decomposition,
carbon dioxide
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Th
Li C l
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The Limestone Cycle
Calcium Carbonate
(limestone)
Calcium Oxide
Calcium Hydroxide
Step 1:heat
Step 2:add a littlewater
Step 3: addmore waterand filter
Step 4:add CO2
CO2
Calcium Hydroxide solution
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Th l d i i f b
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04/08/2013Thermal decomposition of carbonates
Limestone undergoes thermal decomposition when heated. Thesame happens to other carbonates. For example, consider
copper carbonate:
Limewater
Copper carbonate(green) turns intocopper oxide (black)
Limewater goescloudy due to carbondioxide being made
Copper carbonate copper oxide + carbon dioxide
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Th P i di T bl
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H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
The Periodic TableRecall something we said earlier some of the
elements are metals:These elementsare metals
This line dividesmetals from non-metals
These elements are
non-metals
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Properties of metals
Metals have very high melting points (which means that they are usually
_____) whereas non-metals will melt at lower ___________All metals conduct heat and __________ very well, whereas non-metalsdont (usually)
Metals are strong and ______ but bendable. Non-metals are usually
_____ or they will snap.Metals will _____ when freshly cut or scratched, whereas non-metals areusually dull.
Metals have higher _______ than non-metals (i.e. they weigh more)
Metals can be used to make ______ (a mixture of different metals)Words - alloys, electricity, solids, weak, densities,
temperatures, tough, shine
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04/08/2013Extracting Metals
A METAL ORE is a mineral or mixture ofminerals from which it is economicallyviable to extract some metal.
To extract a metal from a metal oxide we need to REDUCE
the oxygen. This is called a REDUCTION reaction. To put itsimply:
Most ores contain METAL OXIDES (e.g. rust = iron oxide).
Some definitions:
Iron OxideIronore
Reduce the oxygento make iron
04/08/2013How do we do it?
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OxideIron
How do we do it?Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
LeadCopper
Silver
Gold
Platinum
Metals ABOVE CARBON, becauseof their high reactivity, are
extracted by ELECTROLYSIS,which is very expensive!
Metals BELOW CARBON areextracted by heating them withcarbon in a BLAST FURNACE.This is a displacement reaction
These LOW REACTIVITY metalswont need to be extracted becausethey are SO unreactive youll find
them on their own, not in a metal oxide
Carbon
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04/08/2013Extracting metals
1) What is an ore?
2) In what form are metals usually found in the Earth?
3) How do you get a metal out of a metal oxide?
4) What is this type of reaction called?
Type of metal Extraction process Examples
High reactivity (i.e anythingabove carbon)
Middle reactivity (i.e.anything below carbon)
Low reactivity
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Th T iti M t l
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04/08/2013The Transition Metals
1) This section includes metals like gold, mercury, iron, copper
Somefacts
2) They are all ______ and solid (except _________)
3) They are ____ reactive than the alkali metals
Words hard, coloured, mercury, less, catalyst, insoluble
4) They can form __________ compounds, usually _______5) They can be used as a ______ (a chemical that speeds up areaction)
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C Al i i d Tit i
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/ /Copper, Aluminium and Titanium
Metal Uses and why Extraction method Problems
Copper Electrical wires good conductor
Electrolysis Limited supply
Aluminium andtitanium
Planes light andcorrrosionresistant
Complicated andexpensive
Expensive anddifficult to extract
Supplies of any raw material are limited so what are the
options?
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Using Iron
Iron produced by the blast furnace (cast iron) contains
about 96% iron and 4% impurities. These impurities make itvery brittle and easy to break.
Ironbridge, Shropshire made out of cast ironand safe for horses and
carts but not modernvehicles.
04/08/2013Usin Ir n
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Using Iron
In pure iron all
impurities areremoved. Thismakes the iron soft:
Adding 1% impuritiesmakes the iron muchstronger:
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Making steel
Amount ofcarbon
added (%)0.5% 1%
Strong
Weak
1.5%
Strength
Hardness
Steel with a lowcarbon content iseasily shaped
Steel with a highcarbon content isstrong but brittle
Steel with chromiumand nickel is calledstainless steel
04/08/2013Alloys
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AlloysSteel is an alloy i.e. a mixture of metals. Here are otheralloys:
Gold mixed with
copper
Aluminium mixed
with magnesiumand copper
Aluminiun mixed
with chromium
04/08/2013Electrolysis
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Electrolysis
+++
+
---
-
Positive
electrode
Cu2+
Cu2+
Cu2+
Negative
electrode
Cl-
Cl-
Cl-
Solution
containingcopper andchloride ions
04/08/2013Electrolysis
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Electrolysis
Electrolysis is used to separate a metal from its compound.
= chloride ion
= copper ion
When we electrolysedcopper chloride the _____chloride ions moved to the
______ electrode and the______ copper ions movedto the ______ electrodeOPPOSITES ATTRACT!!!
Extracting and purifying copper04/08/2013
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Extracting and purifying copperCopper can be extracted from copper-rich ores by heating theores in a furnace and then purifying it by electrolysis.
Extracting copperuses large amounts of
heat and energy
Bingham Canyon coppermine in Utah, one of the
largest in the world
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Purifying Copper by electrolysis
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Purifying Copper by electrolysis
+++
+
---
-
Solution
containingcopper ions
Impure
copper
Cu2+
Cu2+
Cu2+
Pure copper
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New ways of extracting copper
Mining lower-grade ____
Phytomining growing_____ that absorb metals
and then ______ them toextract the metal from __.
Bioleaching using ______ toproduce leachate solutions thatcontain metal _________.
Words compounds, plants, ores, bacteria, burning, ash
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Extracting Aluminium
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Extracting Aluminium
Aluminium has to be extracted from its ore by electrolysis. This isbecause aluminium is very ___________ and so it cannot be extracted
using ______. The amount of energy and _____ required to extractaluminium and other metals is very high and so ________ is a muchbetter option.
Words reactive, recycling, money, carbon
Extracting metals from soil04/08/2013
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Extracting metals from soil
Where metals have
contaminated land (e.g.brown field sites), plantssuch as brassica can be usedto extract the metals back
out of the soil and the metalscan then be recovered fromthe plants.
04/08/2013Crude Oil
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Crude Oil
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Hydrocarbons and crude oil
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Hydrocarbons and crude oil
Longer chains mean
1. Less ability to flow
2. Less flammable
3. Less volatile
4. Higher boiling point
In
creasing
le
ngth
Crude oil is a mixture of HYDROCARBONS
(compounds made up of carbon and hydrogen).Some examples:
Ethane
C C
HH
H
HH
H
Butane
C CHH H
HH
H C C HH
HH
04/08/2013Distillation rev
ision
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Distillation revision
This apparatus can be used to
separate water and inkbecause they have different
_____ ______. The ______will evaporate first, turn backinto a _______ in the
condenser and collect in the_______. The ink remains inthe round flask, as long as the
_______ does not exceedinks boiling point. This
method can be used toseparate crude oil.
Words temperature, boiling points, water, beaker, liquid
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Fractional distillation
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Fractional distillationCrude oil can be separated by fractional distillation. The oil is evaporatedand the hydrocarbon chains of different lengths condense at differenttemperatures:
Fractions withlow boilingpoints condense
at the top
Fractions withhigh boilingpoints condenseat the bottom
04/08/2013Alkanes
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AlkanesAlkanes are SATURATED HYDROCARBONS. What does thismean?
HYDROCARBONS are molecules that are made up ofhydrogen and carbon atoms
SATURATED means that all of these atoms are held
together by single COVALENT bonds, for example:
Ethane
Alkanes are fairly unreactive (but they do burn well). The
general formula for an alkane is CnH2n+2
C C
HH
H
HH
H
Butane
C C
HH H
HH
H C C H
H
HH
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General Formulae for Alkanes
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General Formulae for AlkanesInstead of circles, lets use letters
General formula for alkanes = CnH2n+2
Butane (n=4)
H
C C
H
HH
H
C C
H
HH
H H
Methane (n=1)
H
C H
H
H
Ethane (n=2)
H
H
C C
H
HH
H
Propane (n=3)
H
C H
H
H
C C
H
HH
H
04/08/2013Burning Fossil
Fuels
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Burning Fossil FuelsBurning fossil fuels like oil and coal causes pollution.
Oil contains carbon:
C
H
H
H
HO
O
OO
OH H
OH H
CO
O
Carbon dioxide is a greenhousegas it helps cause global warming
Coal contains carbon, sulfur and other particles:sulfur + oxygen sulfur dioxide
Sulfur dioxide causes acid rain. Other particles cancause global dimming sunlight is absorbed by the
particles in the atmosphere.
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Removing SulfurSulfur dioxide is clearly bad for the environment so its a goodidea to remove as much sulfur as possible:
Vehicles can remove sulfurfrom fuels before theyare burned.
Power stations can removesulfur dioxide from wastegases after combustion.
04/08/2013Other fuel sources
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Other fuel sources
Task: Identify two other fuel sources (biofuels) currently
being developed and find out the following:
1) What is the source called and what is it made of?
2) Why is the fuel better than coal?
3) What are the disadvantages of this fuel?
04/08/2013Using Crude Oil
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Using Crude Oil
Crude Oil
Benefits Drawbacks
Cheap toextract
Wide range ofuses as fuel
Used to makeplastics
Plastics dontbiodegrade
Burning
fossil fuelscauses
pollution
Disposal ofmaterials
uses up landfill sites
Itsgoing torun out
04/08/2013Disposal
of plastics
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Disposal of plastics1) Landfill sites - most plastics do not
_________ which means that landfill sitesare quickly filled up. Research is beingcarried out on __________ plastics.
2) Burning this releases carbon
dioxide which causes the________ effect, as well asother ________ gases.
3) _______ the best option, butdifficult because of the differenttypes of plastic
Words recycling, greenhouse,
decompose, biodegradable, poisonous
04/08/2013Ethanol
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EthanolEthanol is an important chemical. Many
countries are increasing the amount ofethanol put into their petrol supplies:
Ethanol is a clean burning energy source and produces littleor no greenhouse gases. How is it made and what are the
advantages and disadvanatges of each method?
Ford Escape E85 runs on 85% ethanol
The fossil fuel way
The renewable way
Ethene + steam ethanolEthene is produced bycracking oil
Sugar ethanol + carbon dioxide
Sugar is produced fromstandard crops like
sugar cane and corn
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Making ethanol from ethene
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Making ethanol from ethene
Ethene
Reaction vessel with hightemperature and pressure
and a catalyst Ethanol
Unused ethene recycled
Ethene + water ethanol
C2H + H20 C2H5OH
04/08/2013Cracking
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CrackingShorter chain hydrocarbons are in greater demand becausethey burn easier. They can be made from long chain
hydrocarbons bycracking
:
Butane
Ethane
For example, this bondcan be cracked togive these:
Ethene
04/08/2013Cracking
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Cracking
This is a THERMAL DECOMPOSITION reaction,with clay used as a catalyst
1) Carbon dioxide causes the _________ effect
2) Sulfur dioxide causes _____ _____
3) Plastics are not _____________
Cracking is used to produce plastics such as polymers and polyethanes. The
waste products from this reaction include carbon dioxide, sulfur dioxideand water vapour. There are three main environmental problems here:
Long chainhydrocarbon
Heatedcatalyst
Gaseoushydrocarbon
Liquid
hydrocarbon
04/08/2013Alkenes
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AlkenesAlkenes are different to alkanes; they contain DOUBLECOVALENT bonds. For example:
Ethane Ethene
Butane Butene
This double bond means that alkenes have the potential to joinwith other molecules this make them REACTIVE. Alkenes
turn bromine water colourless.
ALKANES
ALKENES
Testing for alkenes 04/08/2013
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Testing for alkenes
Oil Bromine goescolourless
Brominewater
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General Formulae for Alkenes
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General Formulae for Alkenes
General formula for alkenes = CnH2n
Propene (n=3)
H
C H
H
H
C C
H
H
Ethene (n=2)
H
H
C C
H
H
Butene (n=4)
H
C C
H
HH
H
C C
H
H H
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Monomers and Polymers
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Monomers and Polymers
C CHH
HH
Ethene
Heres ethene again. Ethene is called aMONOMER because it is just one smallmolecule. We can use ethene to makeplastics
Step 1: Break the double bond
Step 2: Addthe molecules
together:
This molecule is called POLYETHENE,and the process that made it is called
POLYMERISATION
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Another way of drawing it
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Another way of drawing itInstead of circles, lets use letters
Ethene
C C
HH
HH
C C
HH
HH
Ethene
H
C C
H
HH
H
C C
H
HH
Poly(e)thene
General formula for addition polymerisation:
C Cn C C
n
e.g. C Cn
H CH3
HH
C C
n
H CH3
HH
04/08/2013Some examples
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Some examples
C C n
H H
HH
C Cn
H H
HCl
C Cn
H H
HH
C CnH H
HCl
C CnH Cl
HBr
C Cn
H Cl
HBr
04/08/2013
Uses of addition polymers
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Uses of addition polymersPoly(ethene) Poly(propene)
Poly(chloroethene), PVCPoly(styrene)
Biodegradable carrier bags04/08/2013
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Biodegradable carrier bags
This carrier bag has been made with flax fibre fromindustrial waste.
04/08/2013
Measuring Energy in Food
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Measuring Energy in Food
The energy contentin foods is measured
in Joules and calories
Foods with large carbohydrate and fatcontents have lots of energy, but toomuch energy and too little exercise
could lead to obesity.
04/08/2013Vegetable Oils
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Vegetable O ls
Use of oil Benefits Drawbacks
Oily foods
Fuel
When plants photosynthesise they produce glucose. They canalso produce vegetable oils and we can use these for food and
fuel:
04/08/2013Extracting Oil
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E tract ng O
Step 1: Crush
the plant
Step 2: Remove oilby pressing
OR step 3: Removeoil by distillation
Why use oil for cooking?04/08/2013
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W y f g1) Why do we use oil for cooking and not just water?
2) What are the problems associated with using oil in cooking?
04/08/2013
Healthy and Unhealthy Oils
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y y
Unhealthy oils:
Healthy oils:
Saturated
Unsaturated
04/08/2013
Saturated vs. Unsaturated Fats
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Some oils are more healthy than others. Fish
oils contain the nutrients Omega-3 and Omega-6. These oils are unsaturated like ethene:
C C
HH
HH
Ethene
Testing for double bonds:
Clearly, it is important forscientists to be able to test if
a food contains healthyunsaturated fats orunhealthy saturated fats.Heres how its done:
Oil (in ethanol)Bromine goescolourless
Bromine
water
04/08/2013
Turning unsaturates into saturates
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g
The unsaturated fat is hardened byhydrogenation
.
Hydrogenated oils have a higher melting point and soare solid at room temperature, making them useful forspreads and pastries.
600C, Nickel catalyst
04/08/2013Emulsions
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Whats an emulsion?
Its a mixture of oil and
water, like in salad dressing
Paint is an emulsion. Other examples:
Milk Cream Butter
Butterfat
Watery liquid
04/08/2013
Why use emulsions?
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yEmulsions can have varying textures and this makes themuseful. Some examples:
Differentthicknesses
of cream
Paint andmayonnaise
04/08/2013Emulsifiers
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An emulsifier is an additive that will stop oiland water from seperating, like in mayonnaise.
How they work:
Water Oil
Im an emulsifier Illsort this out with my
hydrophobic end andmy hydrophilic end!I dont want tomix with you!
The water and oil drops become coated and insulated from
one another, which prevents them from seperating.
04/08/2013
Uses of emulsifiers in food
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Emulsifiers are used:
1) In bread, to stop large _____ developing when it bakes
2) In low fat spreads, to allow the oil and water to be _____
3) In ice cream and spray cream, to ______ the foam
4) In sponge cakes, to make tiny pockets of ____
5) In chocolate, to stop melted chocolate forming _______
Words crystals, air, holes, mixed, stabilise
04/08/2013
The Structure of the Earth
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A thin crust -10-100km thick
A mantle has theproperties of a solidbut it can also flow
A core made of
molten nickel and iron.Outer part is liquidand inner part is solid
The average density of the Earth is much higher than
the crust, so the inner core must be very dense
04/08/2013
Movement of the Lithosphere
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pThe Earths LITHOSPHERE (i.e. the _______) is splitup into different sections called ________ plates:
These plates are moving apart from each other afew centimetres every _______ due to the________ currents in the mantle caused by the________ decay of rocks inside the core.
Words radioactive, crust, convection, tectonic, year
04/08/2013Plate Movements
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Oceanic Crust
Mantle
Magma
Convection
Currents
Earthquakes andvolcanic eruptions can
be common here
04/08/2013The
Earths Atmosphere
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p
Carbon dioxide, water vapour Oxygen Nitrogen Noble gases
For the last 200 million years the atmosphere has remained roughly thesame it contains 78% nitrogen, 21% oxygen, 1% noble gases and about
0.03% CO2
04/08/2013Evolution of the E
arths Atmosphere
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4 Billion years 3 Billion years 2 Billion years 1 Billion years Present day
Carbon
dioxide
Methane Ammonia Oxygen Nitrogen Others
Present dayatmosphere contains78% nitrogen, 21%oxygen, 1% noblegases and about0.03% CO
2
04/08/2013Evolution of the E
arths Atmosphere
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4 Billion years 3 Billion years 2 Billion years 1 Billion years Present day
Volcanic activityreleases CO2, methane,ammonia and water
vapour into theatmosphere. The watervapour condenses toform oceans.
Some of the oxygen isconverted into ozone.
The ozone layer blocksout harmful ultra-violetrays which allows for thedevelopment of new life.
Green plants evolve which take in CO2 andgive out oxygen. Carbon from CO2
becomes locked up in sedimentary rocks ascarbonates and fossil fuels. Methane andammonia react with the oxygen andnitrogen is released.
One theory about how life was formed04/08/2013h d l h
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The Primordial Soup theory:
A collection ofsimple molecules
like methane
Amino acids
Dr StanleyMiller 1930-
2007
In 1953 I conducted an experiment thatproved that an electrical discharge can turnmethane into amino acids! This is called the
Miller-Urey experiment.
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Carbon dioxide in the atmosphereTh f CO h h ff d b 3 h
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The amount of CO2 in the atmosphere is affected by 3 things:
1) Geological activity moves carbonate rocks deep into
the Earth and they release ______ _______ into theatmosphere during volcanic activity.
2) When fossil fuels are burned the carboncontained in them reacts with _____ to form CO2.
3) Increased CO2 in the atmosphere causes a reactionbetween it and _______. These reactions do not remove ALLof the new CO2 so the greenhouse effect is still getting
_______!
Words oxygen, seawater, carbon dioxide, worse
04/08/2013Separating air
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p gAir can be separated into the different gases that make it up.To do this you first have to cool air down to -2000C and turn it
into a liquid:
Liquid air
(-200OC)Fractionaldistillation
In this chamber the air is gradually heated up again and
Nitrogen
Argon
Oxygen
RemoveCO2 and
H2O vapour