View
216
Download
0
Category
Preview:
Citation preview
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 1/401www.bangor.ac.uk GCSE Science: Chemistry 1
Contents
Elements 2
Physical Properties 3
The Periodic Table- Mendeléev 4Compounds 5
The Ionic Bond 6
Formulae 7
Metals 8
Displacement Reactions 9
The Blast Furnace 11Electrolysis of Lead (II) Bromide 12
Electrolysis - Aluminium 13
Uses of Metals 15
Nano Science 16
Non-metals - Electrolysis of water 18
Uses of non-metals 20Fluoridation of water supply 21
Acid Reactions 23
Method for preparing crystals 27
Fuels – Crude Oil 28
Cracking 30
Making Plastics(Polymerisation) 31Properties of Plastics 31
Tectonic Plates - Wegener 32
The Atmosphere 35
Global Warming 37
Acid Rain 38
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 2/402 GCSE Science: Chemistry 1 www.bangor.ac.uk
Atom
The Periodic Table - Basics
Elements
Elements are the building blocks of all substances.They cannot be broken down into simpler substancesby chemical means
An Element contains only one type of atom
Na+
Na+ Na
+
Na+
Na+ Na
+
Na+
Na+
Na+
Each atom has negatively charged electrons orbiting apositively charged nucleus
Element
Nucleus
(positive)
Neutron
Proton
Shell
Electron
(negative)
Protons are positive, neutronsare neutral (no charge). This iswhy the nucleus has an overall
positive charge
Group There are eight groups
Period
1
2
3
4
5
6
7
Describing PositionSodium is in Group 1, Period 3Helium is in Group 0, Period 1
Beryllium is in Group 2, Period 2
d o w n
across
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 3/403www.bangor.ac.uk GCSE Science: Chemistry 1
M e
t a l s
N o n - M e t a l s
C o n d u c t
E l e c t r i c i t y
C o n d u c t
H e a t
H i g h
M e l t i n g p o i n t
B o i l i n g p o i n t
M a l l e a b l e
D u c t i l e
C a n b e h a m m e r e d i n t o s h e e t s
C a n b e p u l l e d i n t o w i r e s
D o e s n o t
c o n d u c t
E l e c t r i c i t y
D o e s n o t
c o n d u c t
h e a t
L o w
M e l t i n g p o i n t
B o i l i n g p o i n t
N o t m a l l e a b l e
N o t d u c t i l e
P h y s i c
a l P r o p e r t i e s
M e t a l s
N o n
M e t a l s
E l e m e n t s c h a n g e f r o m b
e i n g m e t a l s
t o n o n - m e t a l s o n g o i n g f r o m
l e f t t o r i g h t a c r o s s t h e P e r i o d i c T a b l e
M a n y e l e
m e n t s i n G r o u p 3 ,
4 ,
5 s h o w
m e t a l l i c a n d n o n - m e t a l l i c
p r o p e r t i e s
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 4/404 GCSE Science: Chemistry 1 www.bangor.ac.uk
Periodic Table
Scientists as far back as 1817 found patterns in the reactivityof elements; however it was Mendeléev (1869) who firstarranged the elements in a layout recognisable as a PeriodicTable.
He placed the elements into 8 groups, in each group elementsreacted similarly. Elements were arranged according to
1. Increasing atomic mass (top number)2. Similar chemical properties
Confident in his work he left gaps predicting that someelements that were not discovered at the time should beplaced there as they would have similar properties
In the old group1there are differentelements such asCopper, Silver andGold
Group 8 and notGroup 0 like today.
Group 4 has many elements which are inthe transitional group today
The periodic table is alsoarranged by now in increasingatomic number (bottomnumber)There are many moreelements now as scientistshave discovered them overthe years. These elementshave fitted into the gaps left byMendeléev.
Gaps where he
predicted an elementwith similar propertiesshould exist
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 5/405www.bangor.ac.uk GCSE Science: Chemistry 1
e.g.
Mg + 2HCl MgCl2 + H2
Compound Formula No. ofelements
No. of atoms
Sodium Chloride NaCl 2 2 (1 Na, 1 Cl)
Sodium Hydroxide NaOH 3 3 (1 Na, 1 O, 1 H)
Sodium Oxide Na2O 2 3 (2 Na, 1 O)
Sodium Sulfate Na2SO4 3 7 (2 Na, 1 S, 4 O)
Calcium Carbonate CaCO3 3 5 (1 Ca, 1 C, 3 O)
Compounds Substance that contains two or more elements joined together chemically
H H
O
Formula
H2O
H2OElements
Atoms
Hydrogen
Oxygen
2 Hydrogen
1 Oxygen
Number of atoms = 3
Number of elements = 2
Chemical Reactions Atoms are rearranged but none are created or destroyed
Same number of atoms in reactants and products, atoms are differentlyarranged.
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 6/406 GCSE Science: Chemistry 1 www.bangor.ac.uk
Ionic Compounds
When a chemical reaction takes place new bonds are formed. Ionic compoundsform by the transfer of electrons from metal to non-metal atom. Chargedparticles called ions are formed
e.g.When sodium chloride (NaCl) forms, one electron is transferred from sodium tochlorine. This will form a full stable outer shell (like noble gasses) for the twoparticles
The Ionic Bond
One electronlost
One electrongained
POSITIVE ION NEGATIVE ION
ElectronTransfer
Ions held together by attractionbetween their opposite charges
METAL NON-METAL
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 7/407www.bangor.ac.uk GCSE Science: Chemistry 1
Using ions to create formulae
Lithium = Li+
Sodium = Na+
Potassium = K +
Magnesium = Mg2+
Calcium = Ca2+
chloride = Cl-
bromide = Br-
iodide = I-
oxide = O2-
sulfide = S2-
SodiumChloride
MagnesiumOxide
LithiumOxide
MagnesiumChloride
Na+ Cl- Mg2+ O2- Li+ O2- Mg2+ Cl-
Li2O MgCl2 MgO
Ions cancelIons cancel
NaCl
Sulfate= SO42-- Carbonate = CO3
2-- Nitrate = NO3-
Sodium
Hydroxide
Na+ OH-
Ions cancel
NaOH
MagnesiumHydroxide
Mg2+ OH-
Ions cancel
Mg(OH)2
Li+
Ions cancel
OH-
Two sets of OH-
(brackets used)
SodiumCarbonate
Na+ CO3--
Ions cancel
Na2CO3
Na+
CalciumCarbonate
Ca CO3--
Ions cancel
CaCO3
Hydroxide= OH-
Cl-
Ions cancel
Quick method
LithiumOxide
Li+ O2-
Li2O
SodiumCarbonate
Na+ CO3--
Na2CO3
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 8/408 GCSE Science: Chemistry 1 www.bangor.ac.uk
The Reactivity
Series
Potassium
Sodium
Calcium
Magnesium
Aluminium
(Carbon)
Zinc
Iron
Lead
Hydrogen
Copper
Silver
Gold
Extraction of Metals
Ores – Metals are found in compounds in rocks which make up the Earth’s crust, these
are called ores
Ore Formula Metal extracted
Bauxite Al2O3 AluminiumHaematite Fe2O3 Iron
Extraction is the term for getting pure metal out of the ore; there are two methods ofextracting metals which depend on their reactivity
Reduction is the process of removing oxygen from the ore using carbon
Electrolysis is the process of using electricity to extract a metal
Reactivity Series – metals are placed in order of reactivity by reacting them withoxygen, water and acid. From this data a reactivity series is produced
At the top metals naturally bond to oxygen stronger which makes it difficult to remove.
I n c r e a s
i n g R e a c t i v i t y
Metals more reactive than carbon
are extracted using
ELECTROLYSIS
Metals less reactive than carbon
are extracted by CHEMICAL
REDUCTION using CARBON
Unreactive - occur naturally as
elements NATIVE
Extraction Method
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 9/409www.bangor.ac.uk GCSE Science: Chemistry 1
Reduction is the loss of oxygen from a compound
Oxidation is the gain of oxygen to form a compound
Magnesium + copper oxide magnesium oxide + copper
iron oxide + carbon carbon monoxide + iron
Iron oxide + aluminium aluminium oxide + iron
Iron oxide and carbon monoxide
Heat
reduction
oxidation
Displacement Reactions
reduction
oxidation
Magnesium and copper oxide
Heat
Mg + CuO MgO + Cu
Fe2O3 + 3CO 3CO2 + 2Fe
reduction
oxidation
The Thermite Reaction Fe2O3 + 2 Al Al2O3 + 2Fe
Blast Furnace Reaction
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 10/4010 GCSE Science: Chemistry 1 www.bangor.ac.uk
iron + copper chloride copper + iron chloride
iron is more reactive than copper, as a result iron displaces copper
copper + silver nitrate silver + copper nitrate
copper is more reactive than silver, as a result copper displaces silver
zinc + copper sulfate copper+ zinc sulfate
zinc is more reactive than copper, as a result zinc displaces copper
Displacement Examples
Iron and copper chloride Fe + CuCl2 Cu + FeCl2
copper and silver nitrate* Cu + 2AgNO3 2Ag + Cu(NO3)2
zinc and copper sulphate* Zn + CuSO4 Cu + ZnSO4
* higher tier only
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 11/4011www.bangor.ac.uk GCSE Science: Chemistry 1
The Blast Furnace – The extraction of iron
Carbon (coke) and oxygen (from the hot air) produce carbon monoxide and gives off
heat. Reduction is achieved by Carbon monoxide at a high temperature
Iron oxide + carbon monoxide iron + carbon dioxide
Fe2O3 + 3 CO 2 Fe + 3 CO2
4. Hot airraw material
1600˚C
Molten iron
slag
Raw Materials1. Iron ore2. Limestone
3. Coke Waste gases
There are 4 raw materials; iron ore, coke, limestone and hot air
Iron ore – the source of iron
Coke – a fuel that producescarbon monoxide for the
reduction reaction
Limestone – to remove impurities.
Limestone breaks down and reacts withsand from the rocks to form slag
Hot air – the fourth raw material
Required for coke to burn
Getting the furnace up to temperature takes a lot of time and costs a lot. As a result
raw materials are constantly added and products removed – the process is continuous.
At the factory in Port Talbot iron ore, limestone and coke are imported from othercountries even though they are available in Wales. Using raw materials from Wales isnot sustainable due to cost and the effect it could have on the environment(quarrying).
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 12/4012 GCSE Science: Chemistry 1 www.bangor.ac.uk
At the positive electrode / anode
2Br- - 2e
-Br2
At the negative electrode /cathode
Pb2+ + 2e-
Pb
Electrolysis of Lead (II) Bromide
The positive ions Pb + move towards the cathode where they gain electrons
The negative ions Br-
move towards the anode where they lose electrons
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 13/4013www.bangor.ac.uk GCSE Science: Chemistry 1
Electrolysis is the method used to extract aluminium from aluminium oxide Asaluminium is a reactive metal, aluminium oxide is very stable, a more powerfulmethod is needed to break the bonds
Electrolysis is the decomposition of a compound using electricity.
Electrodes carry the current into and out of themolten compound, they are conducting rods. Oneis positive and the other is negative.
Anode = positive electrode
Cathode = negative electrode
Electrolyte is a solution containing ions.**Must be dissolved or molten to allow ions to move and carry charge**
Aluminium Extraction (Separating aluminium oxide to create aluminium)
Electrolyte = molten aluminium oxide (950˚C)
Electrodes = Carbon
Both electrodes are placed in molten aluminium oxide (electrolyte). This containsions of aluminium (+ charge) and oxygen (- charge). These are able to movewhen molten and therefore allow conduction of electricity.
Electrolysis of Aluminium Oxide
negative electrode
cathode
positive electrode
anode
molten aluminium
oxygen gas
molten aluminium
oxide (electrolyte)
Al +
Al3+
O2-
O -
O2-
O2-Al +
O2-
Al +
O2-
Positiveelectrode
Electrolyte
negativeelectrode
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 14/4014 GCSE Science: Chemistry 1 www.bangor.ac.uk
Aluminium ions are attracted to the negative electrode (cathode)
Oxygen ions are attracted to the positive electrode (anode)
Aluminium has many uses due to its physical properties
Uses Property
Car manufacturing Resistant to corrosion
Power lines Electrical conductivity
Saucepans Heat conduction
Aeroplanes Low density
Locating aluminium plants
Electrolysis is an expensive process as it needs a lot electrical energyconstantly. Most are located next to a power station
Aluminium is reactive so it needs an enormous amount of electricity to separate itfrom oxygen. Also it is expensive as it needs heat energy to heat up the ore to1000˚C
The energy costs associated with aluminium production are very high and whenWylfa Power Station was decommissioned, Anglesey Aluminium closed. When itwas running the plant accounted for around 10-15% of all the electricity used in
Wales. Without a power station close by, guaranteeing the supply of electricity,this became unsustainable and the plant closed.
Factories are located near the coast as they need to import the aluminium orefrom abroad.
To increase the lifetime of metal ores such as aluminium oxide and iron oxide it isnecessary to recycle metals.
Recycling aluminum uses only about 5% of the energy needed to extract it frombauxite and saves waste. Less electrical consumption means less greenhouse
gas (CO2) emissions. The environment is spoilt by quarrying.
Electrolysis of Aluminium Oxide
aluminium ions+ electrons aluminium atoms
Oxide ions – electrons oxygen molecules
Al3+ + 3e Al
2O2- - 4e O2
Reaction at thenegative electrode
cathode
Reaction at thepositive electrode
anode
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 15/4015www.bangor.ac.uk GCSE Science: Chemistry 1
Copper
Copper has many uses due to its physical properties
Uses PropertyJewellery Shiny
electrical Wires Electrical conduction
saucepans Heat conduction
pipes Malleability ( create sheets )
Electrical wires Ductility ( create wires )
Titanium
Titanium is important as an alloying agent with aluminum, molybdenum,
manganese, iron, and other metals. Alloys of titaniumare principally used for aircraft and missiles wherelightweight strength and ability to withstandextremes of temperature are important.
Titanium is as strong as steel, but 45% lighter. It is 60%heavier than aluminium, but twice as strong. Does notcorrode in water. 1660 ºC M.pt
Steel
Steels are a large family of metals. All of them are alloys in which iron ismixed with carbon and other elements. Steels are described as mild, medium-or high-carbon steels according to the percentage of carbon they contain,although this is never greater than about 1.5%.
The metal in the scissors contains nearly twenty times as much carbon and ismany times harder than the steel in a drinking can.
Steel is recycled on a large scale.
Recycling steel saves 50% of the energy used in the extraction of iron.
Recycling helps to conserve iron ore
Recycling cuts down on the emission of greenhouse gases (carbon dioxide)
Type of steel Percentage of carbon Strength
Mild steel Up to 0.25% hard
Medium carbon steel 0.25% to 0.45% harder
High carbon steel 0.45% to 1.50% hardest
An alloy is a mixturemade by mixingmolten metals; theproperties can bechanged by alteringthe amount of eachmetal
Uses of metals
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 16/4016 GCSE Science: Chemistry 1 www.bangor.ac.uk
Nanoscience
Scientists have a great interest in the nano range because the properties of materials can bedifferent than when they are at a larger scale. The properties change from 100 nm downwards.
Comparing sizes in nanometre scale
Many new materials are possible with this technology of building materials from atoms.
Uses which are made from nanotechnology
In fridges
A layer of silveratoms killbacteria, fungus
and viruses.
In sterilising sprays.
Silver particles of nano sizeare sprayed to kill bacteria,
fungus and viruses
H H
O
80,000 nm wide is apiece of hair
7,000 nm o wide is 1 redblood cell
0.3 nm wide is 1 molecule ofwater
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 17/4017www.bangor.ac.uk GCSE Science: Chemistry 1
Self-cleaning glassSun screen
There are nano particles in sunscreens to prevent ultravioletradiation damage to skin cells
causing cancer.
Nanoscience
The new properties of these materials will allow people to create many new products.
Dangers with nano particles
Although there are major benefits to nanoscience , nano particles could potentially harm humansand the environment.
Environmental and human experiments have to be performed on nano particles before they canbe released commercially
As nano particles are so small and light the can move in the atmosphere. They can also move inrivers. These are methods by which nano particles can enter the body.
Dangerous nano particles can
enter the blood stream
Nano-sized TiO2 and ZnO are used,they absorb and reflect UV light.Being transparent is appealing to
customers
Self-cleaning glass is coated with nano-scaleTiO2 particles, which are hydrophobic (waterrepellent), dirt breaks down in sunlight and iswashed away by rainwater.
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 18/4018 GCSE Science: Chemistry 1 www.bangor.ac.uk
Non-metals such as nitrogen, oxygen, neon and argon are obtained from the air.
Composition of the air
Noble Gases = 0.9%
Nitrogen = 78%
Carbon dioxide = 0.04%Oxygen = 21%
Air as a raw material
Electrolysis of water – the Hoffmann Voltameter
Oxygen and hydrogen can be made from the electrolysis of water. The equipment below isused
OxygenHydrogen
Non-metals
Twice the volume of Hydrogen as oxygen is made,this is because the formula of water is H2O. 2H2O (l) 2H2 (g) + O2 (g)
Hydrogen is made at
the cathode
Oxygen is made at the
anode
Water
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 19/4019www.bangor.ac.uk GCSE Science: Chemistry 1
Identifying Hydrogen and oxygen gas
Hydrogen Test
If a lighted splint is placed inhydrogen it will create asqueaky ’pop’ sound.
Oxygen Test
Oxygen will re-light a glowingsplint
It is possible to test for the gases made by the electrolysis of water
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 20/4020 GCSE Science: Chemistry 1 www.bangor.ac.uk
Advantages Disadvantages
Only water is produced and no carbondioxide released – therefore it does notcontribute to global warming.
Large amount of electricity needed toproduce hydrogen in the first place
Does not contribute to acid rain Storage requires bulky and heavypressurised containers
Safe storage is also important as hydrogenmakes an explosive mixture with air
Hydrogen as a fuel
Hydrogen burns in air to make only water. The reaction is exothermic and produces a lot ofenergy. [exothermic – releases energy]
Hydrogen + Oxygen Water
H2 (g) + O2 (g) H2O (l)2 2
Advantages and Disadvantages of Hydrogen as a fuel
Hydrogen is a rocket fuel.
It is also used to power hydrogen fuel cellcars.
Fuel cells were invented by a WelshmanSir William Grove in 1839. It is onlyrecently that they have been used to
power cars. The technology has benefitsand drawbacks.
NOTE: In order for the process to remain green Hydrogen must be made by theelectrolysis of water using renewable energy (solar/wind)
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 21/4021www.bangor.ac.uk GCSE Science: Chemistry 1
Non metals Physical Properties
To fill weatherballoons
Use Properties
To fill lightbulbs
Advertisinglights
low density,very unreactive
Helium
Neon
Element
Seawater compoundse.g.Sodium chloride
Magnesium chlorideMagnesium sulfateSodium Iodide
Chlorine and Iodine canbe produced fromseawater compounds.
Today improved methodsthat are more economicmean that iodine is notextracted from sea water.the concentration of
chlorine compoundsis more than iodinecompounds.
Chlorine
Iodine
poisonous/toxic,kills bacteria
very unreactive
inert atmosphere
emits lightwhen electriccurrent passesthrough it
treatment ofwater supplies
making householdcleaners
treatment ofswimming pool
antiseptic followinghospital procedures
Quantities of chlorinecontrolled andmonitored to kill bacteriaand sterilise the water,without causing any harmto us.
Argon
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 22/4022 GCSE Science: Chemistry 1 www.bangor.ac.uk
Fluoridation of tap water
Addition offluoride
compounds towater supply
Strengthenschildren’s
teeth
Can cause cancer iftoo much is added to
the water supply.
There is a difference of opinion for the addition of fluoride to water supplies.
Scientific studies show that its addition helps strengthen children’s teeth fromdecay (there are reduced number of fillings in areas that have extra fluoride added)
The problems;(1) high concentrations of fluoride can be poisonous and may cause cancer (bone andteeth).(2) It can cause discolouring or decay of teeth (fluorosis) and(3) it can cause infertility.(4) Some people oppose it because they feel it is not right to force everyone to
consume fluoride without the individual’s consent.
Questionnaire – data of the state of children’s teeth are collected by counting the
number of fillings, loss of teeth and decayed teeth children of all ages have.
The data is reliable because all the children of the school are tested with exceptionof absent pupils.
The comparison of areas which have been fluoridated with unfluoridated areas can beunfair without the consideration to other factors (e.g. social and economic) which are
important for those areas.
Collecting evidence
Fluoride is normally in toothpaste, mouthwash and
sometimes it is added to special milk
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 23/4023www.bangor.ac.uk GCSE Science: Chemistry 1
Acid Reactions Hydrochloric AcidSulfuric Acid
H2SO4 HCl
Universal Indicator (pH) = A substance that changes colour whenadded to an acidic, alkaline or neutral substance. The colourcorresponds to the strength of the acid or alkali (e.g. strong or weakalkali)
Strong Acid Weak Acid Weak Alkali Strong AlkaliNeutral
Indicator
Metal oxide or metal hydroxideBase
Most are insoluble in water
Alkali A water soluble base
0 1 2 3 4 5 6 8 9 11 13 1412107
Nitric Acid
HNO3
Sulfuric Acid OrangeOven cleaner
Sodium Hydroxide
Pure
water Soap
ACID + ALKALI SALT + WATER
Hydrochloric Acid + Sodium Hydroxide Sodium chloride + Water
HCl a + NaOH a NaCl a + H2O l
1. Acid + Alkali
Sulfuric Acid + Sodium Hydroxide Sodium sulfate + Water
H2SO4 (aq) + 2NaOH (aq) Na2SO4 (aq) + H2O (l)
Nitric Acid + Sodium Hydroxide Sodium nitrate + Water
HNO3 (aq) + NaOH (aq) NaNO3 (aq) + H2O (l)
NEUTRALISATION REACTIONS
When the correct amount of acid and alkali are
added together a neutral solution is made
Form salts Sulfate Nitrate Chloride
Na O H
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 24/4024 GCSE Science: Chemistry 1 www.bangor.ac.uk
alkali
pH meter
A pH sensor can be used to monitor a neutralisation reaction; in the reaction below
alkali (potassium hydroxide) is added slowly to 25 cm3 acid
Investigating a Neutralisation Reaction
pH 3.4
25 cm3 acid0 – 24 cm – solution is acidic
25.00 cm3
– neutralisation point
26- 50 cm3 – solution is alkaline
(too much alkali added)
Alkali added to Acid
Acid added to Alkali
Volume of acid added / cm3
Volume of alkali added / cm3
If too much acid (excess) isadded the substance will beacidic at the end.
If the correct volume is added(25 cm3) the solution becomes
0 – 24 cm – alkaline25.00 cm3 – neutralisation
point
26- 50 cm3 – acidic
REMEMBER – All neutralisation reactions are exothermic (heat is released)
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 25/4025www.bangor.ac.uk GCSE Science: Chemistry 1
ACID + BASE SALT + WATER
3. Acid + Base
Sulfuric Acid + Copper oxide Copper sulfate + Water
H2SO4 (aq) + CuO (s) CuSO4 (aq) + H2O (l)
2. Acid + Carbonate
ACID + Carbonate SALT + WATER + CARBON DIOXIDE
Sulfuric Acid + Copper Carbonate Copper sulfate + Water + Carbon Dioxide
H2SO4 (aq) + CuCO3 (s) CuSO4 (aq) + H2O (l) + CO2 (g)
Carbon dioxide testCarbonate test
If clear limewater turnsmilky there is carbon
dioxide present.
When acid reactswith a carbonatefizzing is observed.Bubbles are seen as
CO2 is a gas
CO2 is made in addition to salt and water
Hydrochloric Acid + Copper oxide Copper chloride + Water
2HCl (aq) + CuO (s) CuCl2 (aq) + H2O (l)
Sulfuric Acid + Sodium Carbonate Sodium sulfate + Water + Carbon Dioxide
H2SO4 (aq) + Na2CO3 (s) Na2SO4 (aq) + H2O (l) + CO2 (g)
Hydrochloric Acid + Sodium Carbonate Sodium chloride + Water + Carbon Dioxide
2HCl (aq) + Na2CO3 (s) 2NaCl (aq) + H2O (l) + CO2 (g)
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 26/4026 GCSE Science: Chemistry 1 www.bangor.ac.uk
Acid SaltHydrochloric Chloride
Sulfuric Sulfate
Nitric Nitrate
Hydrogen Test
If a lighted splint is placed inhydrogen it will create a squeaky’pop’ sound.
4. Metal + Acid A reactive metal produces hydrogen with acids
METAL + ACID SALT + HYDROGEN
Magnesium + hydrochloric acid Sodium chloride + hydrogen
Mg (s) + 2HCl (aq) MgCl2 (aq) + H2 (g)
Zinc + sulfuric acid zinc sulfate + hydrogen
Zn (s) + H2SO4 (aq) ZnSO4 (aq) + H2 (g)
Acid Reactions Summary
Acid
Salt + Hydrogen
SaltCarbon Dioxide
Water
Alkali Base (Metal
Carbonate)
Salt+ Water
Metal
Salt + Water
Base
(Metal Oxide)
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 27/4027www.bangor.ac.uk GCSE Science: Chemistry 1
Method of preparing salt crystals
Stage 1: Excess base (copper oxide) is added to the dilute acid to make sure all the acidhas been reacted and used up. Heat and stirring will assist the process
Stage 2: The excess (unreacted) base is removed by the process of filtration, using a filterfunnel and filter paper
Stage 3: Salt is obtained by evaporation – water evaporates and crystals of salt leftbehind. Water can be evaporated slowly near a window or with additional heating using a
Bunsen Burner, 1/3 of the solution should be left behind to evaporate naturally.
unreacted
The method below is used to obtain salt from metal oxides and carbonates
Obtaining salt from the metal and acid reaction
The only difference in the method is stage 1 – excess metal is used – to make sure all
the acid has been used up
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 28/4028 GCSE Science: Chemistry 1 www.bangor.ac.uk
Carbon has the ability to form bonds with other carbon atoms resulting in the formationof carbon atom chains, e.g.
Crude oil contains a mixture of different sized hydrocarbon chains
Production and uses of fuels
Formed over millions of years from the remains of simplemarine organisms
Crude oil (petroleum)
There is a limit to coal, crude oil (petroleum) and natural gas life as they will run out overtime – they are finite – or non-renewable.
Remains of simple
marine organisms
Pressure
Heat Sandstone containin oil
Naturalgas(e.g. CH4)
Millions of Years
Crude oil is a mixture of hydrocarbons
Hydrocarbons are compounds that contain the elements hydrogen and carbon only.
S
Example of ahydrocarbon
Some othersubstances are
also present
CC CH
CHH
HH
H
H H
HH
CC CH
CHH
HH
H
H
HH
CC C C
HH
H
HH
H H H H
C C
HH
HH
H HC CH C
HH
HH
H
H
H
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 29/4029www.bangor.ac.uk GCSE Science: Chemistry 1
Production and uses of fuels
Crude oil is separated into fractions The process is called Fractional Distillation
Fractionatingcolumn
Hot crude oil
diesel oil
paraffin/kerosine
naphtha
petrol
Gas
Lubricating oil
Bitumen
1 – 4
4 – 12
7 – 14
11 – 15
C30 – and above
20 – 30
15 – 19
Fraction No. of Carbon
atoms in chain
Boiling point
range / ˚C
Fractions contain hydrocarbons with boiling points in the same range, e.g. the petrol
fraction has hydrocarbons with boiling points in the range 40-100 ˚C
Long chain hydrocarbons are at the bottom of the column as they do not boil until avery high temperature
Some of the fractions are used as fuels (e.g. Kerosine – aeroplane fuel) others are further
processed by cracking. (see next page)
-160 to 25
40 to 100
100 to 150
150 to 250
over 400
over 350
250 to 350
Problems with burning fossil fuels
CO2
SO2
NO2
Global Warming
Acid Rain
CO
Incomplete combustion
C
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 30/4030 GCSE Science: Chemistry 1 www.bangor.ac.uk
When small reactive molecules such as ethene react together in a chemicalreaction a long chain molecule called a polymer is formed.
Monomer is the name given to small reactive organic molecule
The process whereby monomers link to create a polymer is polymerisation.
The type of polymerisation that happen here is addition polymerisation as
there is only one product formed
Cracking and Addition Polymerisation
polymer
monomer
Ethene has a double bond.One of the bond breaks toallow the molecule to join
with another
Cracking
At high temperature long hydrocarbon chains are broken down into smaller, moreuseful hydrocarbons.
This can create ethene.
Decane Octane + Ethene
Ethene is a small reactive molecule, a monomer
If many ethene molecules are linked together it is called polythene which is used to
make many plastics
Used to make the
plastic polythene
Shorter
more useful
Creating Plastics
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 31/4031www.bangor.ac.uk GCSE Science: Chemistry 1
Properties of Plastics
Electrical insulator /flexible
Strong /low density
Strong /low density
Transparent /flexible
Thermalinsulator
There are many types of plastics, all made by polymerisation, e.g. polythene, PVC, PTFE(Teflon) and polystyrene.
Plastics versus traditional materials
Plastics are used widely in place of natural materials such as paper and iron
PVC plastic is used to make water pipes/guttering because they are light, do not rust likeiron, cheaper and last longer
Polythene is used to make plastic bags in place of paper as they are stronger, do not ripand are waterproof
The disadvantages of plastics are that the do not rot i.e. the do not decompose (takeshundreds of years) and fill landfill sites.
With heat some plastics melt easily
If plastics burn they form poisonous gases
Recycling waste plastic:1. reduces the amount of waste but equally importantly
2. conserves crude oil reserves and
3. requires less energy than making new plastics
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 32/4032 GCSE Science: Chemistry 1 www.bangor.ac.uk
Geology
Tectonic plates movements
Lithosphere – outer layer of theearth contains three types of rocks.They create tectonic plates
Plates can move towards each
other. More dense plate (heavy)melts to form magmaMountain ranges can be formedExplosive volcanoes possible
Plates can slide past each other
Tectonic Plates – The lithosphere has been split up into pieces called tectonicplates which move very slowly in different directions as seen in the diagram.
Any movement will cause an earthquake
Plotting the epicentres of major
earthquakes and the sites of activevolcanoes shows the location of plateboundaries
Plates can move apart. Magmapushes through to create newigneous rock (granite)Volcanic eruption possible
Constructive plate Destructive plate
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 33/4033www.bangor.ac.uk GCSE Science: Chemistry 1
Alfred Wegener – Theory of Continental drift
A theory that changed into scientific fact overtime due to enough scientific evidence.
Alfred Wegener idea in 1915 was notscientifically accepted until moreconcrete facts were put forward. At thetime Wegener could not explain WHY the plates moved
Alfred Wegener suggested thatthe Earth's continents wereonce joined
He said the continents hadmoved apart to their presentpositions;
He observed the close fit ofcoastlines, of different countries(continents). Jigsaw fit
He also saw similar patterns ofrocks and fossils, of continentsseparated by large oceans;
CoastlineContinent
Ocean
The current theory of plate tectonicsbecame widely accepted in the 1960's.
By which time other scientists had foundevidence to show that it is the Earth'splates that move and that they do so as aresult of convection currents in the mantle.
Mantle
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 34/4034 GCSE Science: Chemistry 1 www.bangor.ac.uk
Accepting Wegener’s theor y
To convince people that the continents could move (continental drift) new evidence
was needed and found;
1. Study of the ocean floor– large mountain ranges anddeep trenches found. It wasoriginally thought that the
seabed was flat
2. Dating techniques usingradioisotopes – oceaniccrust was very young
compared to the continents
3. Rocks keep a record of themagnetic field of the Earth, whichchanges from time to time.
Evidence of “seafloor spreading”
Crust forms and moves sideways in
both directions
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 35/4035www.bangor.ac.uk GCSE Science: Chemistry 1
Atmosphere
The composition of the air was different 4000 million years ago. Most Scientists agree
that the initial atmosphere came from volcanoes.
Percentage of oxygen in the air
Atmosphere creation
A B C
DE
Volcanoes releasingcarbon dioxide,ammonia and watervapour (steam)creating the firstatmosphere
The Earth coolscausing the steam tocondense, formingoceans. This was
fast.
Photosynthesisingbacteria form in theoceans. Carbondioxide levels
decrease.
Bacteria releasesoxygen in theatmosphere. Oxygen
levels increase.
Oxygen combines toform ozone. Itprevents ultravioletlight from enteringthe Earth. It helps to
prevent skin cancer.
Noble Gases = 0.9%
Nitrogen = 78%
Carbon dioxide = 0.04%Oxygen = 21%
Oxygen reacts withammonia - nitrogenmade – the mostabundant gas in theatmosphere
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 36/4036 GCSE Science: Chemistry 1 www.bangor.ac.uk
Atmosphere
The levels of oxygen and carbon dioxide have remained fairly constant for many years
due to the carbon cycle.
Carbon Cycle
Dros miliynau o flynyddoedd
Resbiradaeth
Resbiradaeth
Dros miliynau o flynyddoedd
Resbiradaeth
Resbiradaeth
Over millions of years
Respiration
Combustion
Oxygen
Carbon dioxidePhotosynthesis
Respiration
Combustion
Oxygen
More carbon dioxide
Photosynthesis
Over the past 100 years
Deforestation
Oil
Coal
Burning fossil fuels
Higher level of carbon dioxide causes thetemperature of the Earth to rise. Heat can
not escape as easily
Global Warming
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 37/4037www.bangor.ac.uk GCSE Science: Chemistry 1
Atmosphere
.
Global Warming
There is evidence to suggest that theEarth is warming but scientists do notall agree on the cause of this.
Many think that it is due mainly toincreased levels of carbon dioxide inthe atmosphere as a result of thecombustion of fossil fuels anddeforestation.
As a result the carbon cycles has beenimbalanced
Heat is kept in
Global warming can cause :-
1. Changing weather patterns e.g.drier, hotter summers in someparts of the world leading todrought.
2. Flooding due to increase rainfallin some areas
3. Quicker melting of ice caps andglaciers
4. Rising sea levels
The effects of global warming
Higher level of carbon dioxidecauses the temperature ofthe Earth to rise. Heat cannot escape as easily
Carbon captureScientists are thinking ofstoring the CO2 produced byburning fossil fuels under thesea or underground in
geological formations
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 38/4038 GCSE Science: Chemistry 1 www.bangor.ac.uk
Acid Rain
In fuels such as oil and petrol there are impurities (i.e. oil is not pure hydrocarbons),compounds such as sulphur and nitrogen are present.
When these burn they form polluting gases, such as sulfur dioxide and oxides ofnitrogen.
Acid rain forms when sulfur dioxide is released from factories. Acid rain forms whensulfur dioxide reacts with rain to form sulfuric acid.
It kills plants (forests) and aquatic life such as fish. It also damages buildings and statuesmade of limestone (calcium carbonate) and metals e.g. bridges.
Acid rain
Sulfur dioxide
Acid rainlowers pH of
lakes
Natural rain water has a pH of 5.5
Acid rain has a pH range of 2-4
Sulfur Scrubbing
The process of removingsulphur dioxide fromexhaust flue gases offossil fuel powered
plants
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 39/4039www.bangor.ac.uk GCSE Science: Chemistry 1
FORMULAE FOR SOME COMMON IONS
POSITIVE IONS
Name Formula
NEGATIVE IONS
Name Formula
Aluminium Al3+
Ammonium NH +
Barium Ba2+
Calcium Ca2+
Copper(II) Cu2+
Hydrogen H+
Iron(II) Fe2+
Iron(III) Fe3+
Lithium Li+
Magnesium Mg2+
Nickel Ni2+
Potassium K+
Silver Ag+
Sodium Na+
Bromide Br –
Carbonate CO 2–
Chloride Cl –
Fluoride F –
Hydroxide OH –
Iodide I –
Nitrate NO –
Oxide O2–
Sulphate SO 2–
4
4
3
3
8/20/2019 GCSE Science - Chemistry 1(1)
http://slidepdf.com/reader/full/gcse-science-chemistry-11 40/40
H e l i u m
N e o n
F l u o r i n e
C h l o r i n e
B r o m i n e
S e l e n i u m
B o r o
n
A l u m i n
i u m
G a l l i u m
Z i n c
C o p p e r
N i c k e l
C o b a l t
I r o n
M a n g a n e s e
C h r o m i u m
V a n a d i u m
T i t a n i u m
S c a n d i u m
mu m
u m
A r s e n i c
P h o s p h o r u s
N i t r o g e n
C a r b o n
S i l i c o n
G e r m a n i u m
S u l p h u r
O x y g e n
A r g o n
K r y p t o n
4 2
N e
2 0
1 0
F 1 9 9
O 1 6 8
C 1 2 6
N 1 4 7
B 1 1 5
A r
4 0
1 8
S
3 2
1 6
P 3 1
1 5
S i
2 8
1 4
A
l
2 7
1 3
K r
8 4
3 6
B r
8
0
3
5
S e
7 9
3 4
A s
7 5
3 3
G e
7 3
3 2
G a
7 0
3 1
Z n
6 5
3 0
C u
6 4
2 9
N i
5 9
2 8
F e
5 6
2 6
C o
5 9
2 7
M n
5 5
2 5
V 5 1
2 3
C r
5
2
2
4
T i
4 8
2 2
S c
4 5
2 1
I o d i n e
T e l l u r i u m
I n d i u m
C a d m i u m
S i l v e r
P a l l a d i u m
R h o d i u m
R u t h e n i u m
M o l y b d e n u m
N i o b i u m
Z i r c o n i u m
Y t t r i u m
m
A n t i m o n y
T i n
X e n o n
X e
1 3 1
5 4
I
1 2 7
5 3
T e
1 2 8
5 2
S b
1 2 2
5 1
S n
1 1 9
5 0
I n 1 1 5
4 9
C d
1 1 2
4 8
A g
1 0 8
4 7
P d
1 0 6
4 6
R u
1 0 1
4 4
R h
1 0 3
4 5
T c
9 9
4 3
N b
9 3
4 1
M o
9 6
4 2
Z r
9 1
4 0
Y 8 9
3 9
A s t a t i n e
P o l o n i u m
T h a l l i u m
M e r c u r y
G o l d
P l a t i n u m
I r i d i u m
O s m i u m
R h e n i u m
T u n g s t e n
T a n t a l u m
H a f n i u m
L a n t h a n u m
B i s m u t h
L e a d
R a d o n
R n
2 2 2
8 6
A t
2 1 0
8 5
P o
2 1 0
8 4
B i
2 0 9
8 3
P b
2 0 7
8 2
T l
2 0 4
8 1
H g
2 0 1
8 0
A u
1 9 7
7 9
P t
1 9 5
7 8
O s
1 9 0
7 6
I r
1 9 2
7 7
R e
1 8 6
7 5
T a
1 8 1
7 3
W
1 8 4
7 4
H f
1 7 9
7 2
L a
1 3 9
5 7
A c t i n i u m
m
A c
2 2 7
8 9
g
H y d r o g e n
H 1 1
3
0
5
6
7
4
G r o u p
P E R I O D I C T A B L E O F E L E M E N T S
H e
C l
3
5
1
7
Z
X
A N
a m e
E l e m e n t S y m b o l
A t o m i c n u m b e r
M a s s n u m b e r
K e y :
T e c h n e t i u m
Recommended