C1 1.1 ATOMS, ELEMENTS & COMPOUNDS

• All substances are made of atoms

• Elements are made of only one type of atom

• Compounds contain more than one type of atom

• Compounds are held together by bonds

•Each element has its own symbol in the periodic table

•Columns are called GROUPS.

•Elements in a group have similar properties

•Rows are called PERIODS

•The red staircase splits metals from non-metals

An atom is made up of a tiny nucleus with electrons around it

C1 1.2 ATOMIC STRUCTURE

• Atoms contain PROTONS, NEUTRONS & ELECTRONS

• Protons and Neutrons are found in the NUCLEUS

• Electrons orbit the nucleus

•ATOMIC NUMBER the number of protons in the nucleus

the periodic table is arranged in this order

•MASS NUMBER the number of protons plus neutrons

Number of neutrons = Mass Number – Atomic Number

Any atom contains equal numbers of protons and electrons

PARTICLE RELATIVE CHARGE

RELATIVE MASS

Proton +1 (positive)

1

Neutron 0 (neutral) 1

Electron -1 (negative)

0

C1 1.3 ELECTRON ARRANGEMENT

• Electrons are arranged around the nucleus in SHELLS (or energy levels)

• The shell closest to the nucleus has the lowest energy

• Electrons occupy the lowest available energy level

•Atoms with the same number of electrons in the outer shell belong to the same GROUP in the periodic table

•Number of outer electrons determine the way an element reacts

•Atoms of the last group (noble gases) have stable arrangements and are unreactive

This is how we draw atoms and their electrons

Low energy shell

High energy shell

Sodium

C1 1.4 FORMING BONDS

• Atoms can react to form compounds in a number of ways:

i) Transferring electrons IONIC BONDING

ii) Sharing electrons COVALENT BONDING

IONIC BONDING

• When a metal and non-metal react• Metals form positive ions• Non-metals from negative ions• Opposite charges attract• A giant lattice is formed

COVALENT BONDING

• When 2 non-metals bond• Outermost electrons are shared• A pair of shared electrons forms a bond

CHEMICAL FORMULAE

• Tells us the ratio of each element in the compound

• In ionic compounds the charges must cancel out:

E.g. MgCl2

We have 2 chloride ions for every magnesium ion

H2 + O2 H2O

Add a 2 to the products side to make the oxygen balance

H2 + O2 2H2O

This has changed the number of hydrogen atoms so we must now adjust the reactant side:

2H2 + O2 2H2O

C1 1.5 CHEMICAL EQUATIONS

• Chemical equations show the reactants (what we start with) and the products (what we end up with)

• We often use symbol equations to make life easier

CaCO3 CaO + CO2

MAKING EQUATIONS BALANCE

Equations MUST balance

We can ONLY add BIG numbers to the front of a substance

We can tell elements within a compound by BIG letters

CaCO3 this is a compound made of 3 elements (calcium, carbon and oxygen)

Ca = 1C = 1O = 3

Ca = 1C = 1O = 3

•This is balanced – same number of each type of atom on both sides of the equation

•We can check this by counting the number of each type on either side

H = 2O = 2

H = 2O = 1

H = 2O = 2

H = 4O = 2

C1 2.1 LIMESTONE & ITS USES

• Limestone is made mainly of Calcium Carbonate

• Calcium carbonate has the chemical formulae CaCO3

• Some types of limestone (e.g. chalk) were formed from the remains of animals and plants that live millions of years ago

USE IN BUILDING

We use limestone in many buildings by cutting it into blocks.

Other ways limestone is used:

Cement = powdered limestone + powdered clay

Concrete = Cement + Sand + Water

HEATING LIMESTONE

Breaking down a chemical by heating is called THERMAL DECOMPOSITION

Calcium Calcium + CarbonCarbonate Oxide Dioxide

CaCO3 CaO + CO2

ROTARY LIME KILN

This is the furnace used to heat lots of calcium carbonate and turn it into calcium oxide

Calcium oxide is used in the building and agricultural industries

C1 2.2 REACTIONS OF CARBONATES

• Buildings made from limestone suffer from damage by acid rain

• This is because carbonates react with acid to form a salt, water and carbon dioxide

Calcium + Hydrochloric Calcium + Water + Carbon

Carbonate Acid Chloride Dioxide

CaCO3 + 2HCl CaCl2 + H2O + CO2

TESTING FOR CO2

• We use limewater to test for CO2

• Limewater turns cloudy

• A precipitate (tiny solid particles) of calcium carbonate forms causing the cloudiness!

HEATING CARBONATES

Metal carbonates decompose on heating to form the metal oxide and carbon dioxide

MgCO3 MgO + CO2

C1 2.3 THE LIMESTONE REACTION CYCLE

• Limestone is used widely as a building material

• We can also use it to make other materials for the construction industry

Calcium Carbonate + Heat Calcium Oxide

Calcium Oxide + Water Calcium Hydroxide (Limewater)

Calcium Carbonate

Calcium Oxide

Calcium Hydroxide

Calcium Hydroxide Solution

Step 1: Add Heat

CaCO3 CaO + CO2

Step 2: Add a bit of water

CaO + H2O Ca(OH)2 Step 3: Add more water & filter

Ca(OH0)2 + H2O Ca(OH)2 (aq)

Step 4: Add CO2

Ca(OH)2 + CO2 CaCO3 + H2OLimestone

C1 2.4 CEMENT & CONCRETE

CEMENT

Made by heating limestone with clay in a kiln

MORTAR

Made by mixing cement and sand with water

CONCRETE

Made by mixing crushed rocks or stones (called aggregate), cement and sand with water

C1 2.5 LIMESTONE ISSUES

BENEFITS

• Provide jobs

• Lead to improved roads

• Filled in to make fishing lakes or for planting trees

• Can be used as landfill sites when finished with

DRAWBACKS

• Destroys habitats

• Increased emissions

• Noisy & Dusty

• Dangerous areas for children

• Busier roads

• Ugly looking

C1 3.1 EXTRACTING METALS

• A metal compound within a rock is called an ORE

• The metal is often combined with oxygen

• Ores are mined from the ground and then purified

Whether it’s worth extracting a particular metal depends on:

How easy it is to extract

How much metal the ore contains

The reactivity series helps us decide the best way to extract a metal:

Metals below carbon in the series can be reduced by carbon to give the metal element

Metals more reactive than carbon cannot be extracted using carbon. Instead other methods like ELECTROLYSIS must be used

THE REACTIVITY SERIES

C1 3.2 IRON & STEELS

• Iron Ore contains iron combined with oxygen

• We use a blast furnace and carbon to extract it (as it’s less reactive than carbon)

• Carbon REDUCES the iron oxide;

Iron (III) Oxide + Carbon Iron + Carbon Dioxide

• Iron from the blast furnace contains impurities:

Makes it hard and brittle

Can be run into moulds to form cast iron

Used in stoves & man-hole covers

• Removing all the carbon impurities gives

us pure iron

Soft and easily shaped

Too soft for most uses

Need to combine it with other elements

• A metal mixed with other elements is called an ALLOY

E.g. Steel Iron with carbon and/or other elements

There are a number of types of steel alloys:

Carbon steels

Low-alloy steels

High-alloy steels

Stainless steels

C1 3.3 ALUMINIUM & TITANIUM

Aluminium Titanium

Property • Shiny• Light• Low density• Conducts electricity and energy• Malleable – easily shaped• Ductile – drawn into cables and wires

• Strong• Resistant to corrosion• High melting point – so can be

used at high temperatures• Less dense than most metals

Use • Drinks cans• Cooking foil• Saucepans• High-voltage electricity cables• Bicycles• Aeroplanes and space vehicles

• High-performance aircraft• Racing bikes• Jet engines• Parts of nuclear reactors• Replacement hip joints

Extraction

Electrolysis

• Aluminium ore is mined and extracted.• Alumminium oxide (the ore) is melted• Electric current passed through at high temperature

Expensive process – need lots of heat and electricity

Displacement & Electrolysis

• Use sodium or potassium to displace titanium from its ore

• Get sodium and magnesium from electrolysis

Expensive – lots of steps involved, & needs lots of heat and electricity

C1 3.4 EXTRACTING COPPER

COPPER-RICH ORES

These contain lots of copper. There are 2 ways to consider:

1. Smelting

• 80% of copper is produced this way

• Heat copper ore strongly in a furnace with air

Copper + Oxygen Copper + SulphurSulphide Dioxide

• Then use electrolysis to purify the copper

• Expensive as needs lots of heat and electricity

2. Copper Sulphate

• Add sulphuric acid to a copper ore

• Produces copper sulphate

• Extract copper using electrolysis or displacement

LOW GRADE COPPER ORES

These contain smaller amount of copper. There are 2 main ways:

1. Phytomining

• Plants absorb copper ions from low-grade ore

• Plants are burned

• Copper ions dissolved by adding sulphuric acid

• Use displacement or electrolysis to extract pure copper

2. Bioleaching

•Bacteria feed on low-grade ore

•These produce a waste product that contains copper ions

•Use displacement or electrolysis to extract pure copper

C1 3.5 USEFUL METALS

TRANSITION METALS

• Found in the central block of the periodic table

Properties:

• Good conductors of electricity and energy

• Strong

• Malleable – easily bent into shape

Uses:

• Buildings

• Transport (cars, trains etc)

• Heating systems

• Electrical wiring

Example: Copper

1. Water pipes – easily bent into shape, strong, doesn’t react with water

2. Wires – ductile and conduct electricity

COPPER ALLOYS

Bronze – Copper + Tin - Tough - Resistant to corrosion

Brass – Copper + Zinc - Harder but workable

ALUMINIUM ALLOYS

•Alloyed with a wide range of other elements

•All have very different properties

•E.g. in aircraft or armour plating!

GOLD ALLOYS

•Usually add Copper to make jewellery last longer

C1 3.6 METALLIC ISSUES

EXPLOITING ORES

Mining has many environmental consequences:

• Scar the landscape

• Noisy & Dusty

• Destroy animal habitats

• Large heaps of waste rock

• Make groundwater acidic

• Release gases that cause acid rain

RECYCLING METALS

• Recycling aluminium saves 95% of the energy normally used to extract it!

• This saves money!

• Iron and steel are easily recycled. As they are magnetic they are easily separated

• Copper can be recycled too – but it’s trickier as it’s often alloyed with other elements

BUILDING WITH METALS

Benefits

• Steel is strong for girders

• Aluminium is corrosion resistant

• Many are malleable

• Copper is a good conductor and not reactive

Drawbacks

• Iron & steel can rust

• Extraction causes pollution

• Metals are more expensive than other materials like concrete

C1 4.1 FUELS FROM CRUDE OIL

CRUDE OIL

• A mixture of lots of different compounds

[A mixture is 2 or more elements or compounds that are not

chemically bonded together]

• We separate it into substances with similar boiling points

• These are called fractions

• This is done in a process called fractional distillation

HYDROCARBONS

Nearly all the compounds in crude oil are hydrocarbons

Most of these are saturated hydrocarbons called alkanes

MethaneCH4

EthaneC2H6

PropaneC3H8

ButaneC4H10

General formula for an alkane is CnH(2n+2)

C1 4.2 FRACTIONAL DISTILLATION

This is the process by which crude oil is separated into fractions

These are compounds with similar sized chains

Process relies on the boiling points of these compounds

The properties a fraction has depend on the size of their hydrocarbon chains

SHORT CHAINS ARE:

Very flammable

Have low boiling points

Highly volatile (tend to turn into gases)

Have low viscosity (they flow easily)

Long chains have the opposite of these!

Crude oil fed in at the bottom

Temperature decreases up the column

Hydrocarbons with smaller chains found nearer the top

C1 4.3 BURNING FUELS

COMPLETE COMBUSTION

Lighter fractions from crude oil make good fuels

They release energy when they are oxidised burnt in oxygen:

propane + oxygen carbon dioxide + water

POLLUTION

Fossil fuels also produce a number of impurities when they are burnt

These have negative effects on the environment

The main pollutants are summarised below

Sulphur Dioxide

• Poisonous gas

• It’s acidic

• Causes acid rain

• Causes engine corrosion

Carbon Monoxide

• Produced when not enough oxygen

• Poisonous gas

• Prevents your blood carrying oxygen around your body

Nitrogen Oxide

• Poisonous

• Trigger asthma attacks

• Can cause acid rain

Particulates

• Tiny solid particles

• Contain carbon and unburnt hydrocarbon

• Carried in the air

• Damage cells in our lungs

• Cause cancer

C1 4.4 CLEANER FUELS

Burning fuels releases pollutants that spread throughout the atmosphere:

CATALYTIC CONVERTERS

• Reduces the carbon monoxide and nitrogen oxide produced

•They are expensive

• They don’t reduce the amount of CO2

GLOBAL DIMMING

• Caused by particulates

• Reflect sunlight back into space

• Not as much light gets through to the Earth

CARBON MONOXIDE Formed by incomplete combustion

GLOBAL WARMING

• Caused by carbon dioxide

• Causing the average global temperature to increase

SULPHUR DIOXIDE

• Caused by impurities in the fuel

• Affect asthma sufferers

• Cause acid rain damages plants & buildings

Carbon + Nitrogen Carbon + NitrogenMonoxide Oxide Dioxide

C1 4.5 ALTERNATIVE FUELS

These are renewable fuels sources of energy that could replace fossil fuels (coal, oil & gas)

BIODIESEL ETHANOL HYDROGEN

+ • Less harmful to animals

• Breaks down 5 × quicker

• Reduces particulates

• Making it produces other useful products

•‘CO2 neutral’ – plants grown to create it absorb the same amount of CO2 generated when it’s burnt

• Easily made by fermenting sugar cane

• Gives off CO2 but the sugar cane it comes from absorbs CO2 when growing

• Very clean – no CO2

• Water is the only product

- •Large areas of farmland required

•Less food produced Famine•Destruction of habitats•Freezes at low temps

• Large areas of farmland required• Less food produced as people use it for fuel instead!

• Hydrogen is explosive

• Takes up a large volume storage becomes an issue

C1 5.1 CRACKING HYDROCARBONS

CRACKING Breaking down large hydrocarbon chains into smaller, more useful ones

SATURATED OR UNSATURATED?

We can react products with bromine water to test for saturation:

Positive Test:

Unsaturated + Bromine COLOURLESS hydrocarbon Water

= ALKENES

Negative Test:

Saturated + Bromine NO RECTIONHydrocarbon Water (orange)

= ALKANES

CRACKING PROCESS

1. Heat hydrocarbons to a high temp; then either:

2. Mix them with steam; OR

3. Pass the over a hot catalyst

EXAMPLE OF CRACKING

Cracking is a thermal decomposition reaction:

C10H22 C5H12 + C3H6 + C2H4

ALKENES

• These are unsaturated hydrocarbons• They contain a double bond• Have the general formula CnH2n

Decane

Pentane Propene Ethene

800oC

C1 5.2 POLYMERS FROM ALKENES

PLASTICS Are made from lots of monomers joined together to make a polymer

HOW DO MONOMERS JOIN TOGETHER?

• Double bond between carbons ‘opens up’• Replaced by single bonds as thousands of monomers join up• It is called POLYMERISATION

MONOMERS POLYMER

EthenePoly(ethene)

nSimplified way of writing it:

‘n’ represent a large repeating number

C1 5.3 NEW & USEFUL POLYMERS

DESIGNER POLYMER Polymer made to do a specific job

Examples of uses for them:

• Dental fillings

• Linings for false teeth

• Packaging material

• Implants that release drugs slowly

Light-Sensitive Plasters

• Top layer of plaster peeled back

• Lower layer now exposed to light

• Adhesive loses stickiness

• Peels easily off the skin

SMART POLYMERS Have their properties changed by light, temperature or other changes in their surroundings

Hydrogels

• Have cross-linking chains

• Makes a matrix that traps water

• Act as wound dressings• Let body heal in moist,

sterile conditions• Good for burns

Shape memory polymers

• Wound is stitched loosely

• Temperature of the body makes the thread tighten

• Closes the wound up with the right amount of force

C1 5.4 PLASTIC WASTE

NON-BIODEGRADABLE

• Don’t break down

• Litter the streets and shores

• Harm wildlife

RECYCLING

• Sort plastics into different types

• Melted down and made into new products

• Saves energy and resources…BUT

• Hard to transport and

• Need to be sorted into specific types

DISADVANTAGES OF BIODEGRADABLE PLASTICS

• Farmers sell crops like corn to make plastics

• Demand for food goes up

• Food prices go up less can afford it STARVATION

• Animal habitats destroyed to make new farmland

• Unsightly

• Last 100’s of years

• Fill up landfill sitesBIODEGRADABLE PLASTICS

• Plastics that break down easily

• Granules of cornstarch are built into the plastic

• Microorganisms in soil feed on cornstarch

• This breaks the plastic down

C1 5.5 ETHANOL

There are 2 main ways to make ethanol

2) ETHENE

Hydration reaction water is added

Ethene + Steam Ethanol

C2H4 + H2O C2H5OH

+ Continuous process – lots made!+ Produces no waste products

- Requires lots of heat and energy- Relies on a non-renewable resource

1) FERMENTATION

Sugar from plants is broken down by enzymes in yeast

Sugar + Yeast Ethanol + Carbon Dioxide

80% of ethanol is made this way

+ Uses renewable resources

-Takes longer to produce- CO2 is given off

A molecule of ethanol

HH-C-C-OH

H

H

H

USES FOR ETHANOL

• Alcohol

• Perfume

• Rocket Fuel

• Solvents

• Antiseptic wipes

C1 6.1 EXTRACTING VEGETABLE OIL

There are 2 ways to extract vegetable oils from plants:

2) DISTILLATION

1. Plants are put into water and boiled

2. Oil and water evaporate together3. Oil is collected by condensing

(cooling the gas vapours)

Lavender oil is one oil extracted this way

1) PRESSING

1. Farmers collect seeds from plants2. Seeds are crushed and pressed3. This extracts oil from them4. Impurities are removed5. Oil is processed to make it into a

useful product

FOOD AND FUEL

Vegetable oils are important foods:

• Provide important nutrients (e.g. vitamin E)

• Contain lots of energy so can also be used as fuels

• Unsaturated oils contain double bonds (C=C) they decolourise Bromine water

Food Energy(kJ)

Veg Oil 3900

Sugar 1700

Meat 1100

Table for info only – don’t memorise it!

C1 6.2 COOKING WITH VEGETABLE OILS

COOKING IN OIL

• Food cooks quicker• Outside becomes crispier• Inside becomes softer• Food absorbs some of the oil• Higher energy content• Too much is unhealthy

HARDENING VEGETABLE OILS

• Reacting vegetable oils with HYDROGEN hardens them increases melting points

• Makes them solid at room temperature makes them into spreads!

• Double bonds converted to single bondsC=C C-C

• Now called a HYDROGENATED OIL

• Reaction occurs at 60oC with a nickel catalyst

+

60oC + Nickel catalyst

Double bonds converted to single bonds

Margarin

e

C1 6.3 EVERYDAY EMULSIONS

Oils do not dissolve in water

Emulsion Where oil and water are dispersed (spread out) in each other

These often have special properties

EMULSION EXAMPLES

1. Mayonnaise2. Milk3. Ice cream4. Cosmetics – face cream, lipstick

etc5. Paint

EMULSIFIERS

• Stop water and oil separating out into layers

• Emulsifiers have 2 parts that make them work:

1.Hydrophobic tail – is attracted to oil

2.Hydrophilic head – is attracted to water. It has a negative charge

Oil droplet

Emulsifier molecule

Water

-

C1 6.4 FOOD ISSUES

E NUMBER

Additives approved for use in Europe

EMULSIFIERS

• Improve texture and taste of foods containing fats and oils

• Makes them more palatable (tasty) and tempting to eat!

FOOD ADDITIVES

Substance added to food to:

• Preserve it• Improve its taste• Improve its texture• Improve its appearance

VEG OILS

Unsaturated Fats:

• Source of nutrients like vitamin E• Keep arteries clear• Reduce heart disease• Lower cholesterol levels

ANIMAL FATS

Saturated Fats:

• Are not good for us• Increase risk of heart disease• Increase cholesterol

E.g. chocolate!

C1 7.1 STRUCTURE OF THE EARTH

Atmosphere:

Most lies within 10km of the surface

Rest is within 100km but it’s hard to judge!

Crust:

Solid

6km beneath oceans

35km beneath land

Core:

Made of nickel and iron

Outer core is liquid

Inner core is solid

Radius is 3500km

Mantle

Behaves like a solid

Can flow very slowly

Is about 3000km deep!

C1 7.2 THE RESTLESS EARTH

MOVING CONTINENTS

The Earth’s crust and upper mantle are cracked into a number of pieces TECTONIC PLATES

These are constantly moving - just very slowly

Motion is caused by CONVECTION CURRENTS in the mantle, due to radioactive decay

PANGAEA

If you look at the continents they roughly fit together

Scientists think they were once one large land mass called pangaea, which then broke off into smaller chunks

PLATE BOUNDARIES

Earthquakes and volcanoes happen when tectonic plates meet

These are very difficult to predict

C1 7.3 THE EARTH’S ATMOSPHERE IN THE PAST

PHASE 1:PHASE 1:Volcanoes = Steam &

CO2

• Volcanoes kept erupting Volcanoes kept erupting giving out giving out Steam and and CO2

• The early atmosphere The early atmosphere was was nearly all COnearly all CO22

• The The earth cooledearth cooled and and water vapour water vapour condensedcondensed to form the to form the oceansoceans

Like this for a billion years!

PHASE 2:PHASE 2:Green Plants,

Bacteria & Algae = Oxygen

• Green plants, bacteria Green plants, bacteria and algae ran riot in and algae ran riot in the oceans!the oceans!

• Green plants steadily steadily converted CO2 into O2 by the by the process of process of photosynthesis

• Nitrogen released by released by denitrifying bacteria

• Plants colonise the land. Oxygen levels steadily increase

PHASE 3:PHASE 3:Ozone Layer = Animals & Us

• The The build up of Obuild up of O22 killed off early killed off early organisms - allowingorganisms - allowing evolution of evolution of complex organismscomplex organisms

• The The O2 created the created the Ozone layer (O3) which blocks harmful which blocks harmful UV rays from the sunfrom the sun

• Virtually no COVirtually no CO22 leftleft

C1 7.4 LIFE ON EARTH

No one can be sure how life on Earth first started. There are many different theories:

MILLER-UREY EXPERIMENT

• Compounds for life on Earth came from reactions involving hydrocarbons (e.g. methane) and ammonia

• The energy for this could have been provided by lightning

OTHER THEORIES

1. Molecules for life (amino acids) came on meteorites from out of space

2. Actual living organisms themselves arrived on meteorites

3. Biological molecules were released from deep ocean vents

The experiment completed by Miller and Urey

C1 7.5 GASES IN THE ATMOSPHERE

THE ATMOSPHERE TODAY:

The main gases in the atmosphere today are:

1. Nitrogen 78%2. Oxygen 21%3. Argon 0.9%4. Carbon Dioxide 0.04%

CARBON DIOXIDE:

• Taken in by plants during photosynthesis

• When plants and animals die carbon is transferred to rocks

• Some forms fossil fuels which are released into the atmosphere when burnt

The main gases in air can be separated out by fractional distillation.

These gases are useful in industry

C1 7.6 CARBON DIOXIDE IN THE ATMOSPHERE

The stages in the cycle are shown below: Carbon moves into and out of the atmosphere due to

• Plants – photosynthesis & decay

• Animals – respiration & decay

• Oceans – store CO2

• Rocks – store CO2 and release it when burnt

CO2 LEVELS

Have increased in the atmosphere recently largely due to the amount of fossil fuels we now burn