1. C1 Revision

2. The periodic table of elements
The periodic table of elements shows us metals (left) and non-metals (right)
Each group has similar chemical properties

3. Atoms The smallest particle of an element
Atoms have the same amount of positive and negative charges so they are neutral
Type of sub-atomic particle
Relative charge
Proton
+1 positive
Neutron
0 (neutral)
Electron -1

4. Mass number Atomic number No. of neutrons = mass no. – atomic no.
Atomic number = number of protons
No. of protons = no. of electrons
The mass number = no. of protons + neutrons
Therefore
No. of neutrons = mass no. – atomic no.

5. Arrangement of electrons
Electrons are arranged around the nucleus of atoms in shells
The first shell can hold up to 2 electrons
The second shell can hold up to 8 electrons
The third shell can hold up to 8 electrons
Then the fourth shell fills up
Lithium
2,1

6. Electrons and the periodic table
Elements in the same group all have the same number of electrons in their outer shell. This means that they share similar properties
Group 1 elements all have 1 electron in the outer shell – they are all very reactive
Group 0 elements (noble gases) have full outer shells – they are unreactive

7. Group 1 – alkali metals
Alkali metals are all soft, stored in oil, low density, react with oxygen and all react violently with water and form alkaline (pH>7) solutions.
Lithium + water  lithium hydroxide + hydrogen
Sodium + oxygen sodium oxide

8. Forming compounds
When atoms of different types of elements join together they form ‘compounds’
When metals react with non-metals they lose or gain electrons & form ions
Metals lose electrons and become positive ions (+)
Non-metals gain electrons – negative ions (-)
Oppositely charged ions are attracted to each other and form an ionic bond

9. Forming compounds
when non-metals react with non-metals they share electrons
This is called covalent bonding
A covalent bond is a shared pair of electrons
solid line Cl – Cl Cl
covalent bond

10. calcium carbonate  calcium oxide + carbon dioxide
Chemical equations
These show us the reactants (on the left) and the products (on the right)
calcium carbonate  calcium oxide + carbon dioxide
CaCO3  CaO CO2
No atoms are lost or made in the reaction and so the total mass of the products is equal to the total mass of the reactants- conservation of mass

11. Limestone Calcium carbonate (CaCO3)
Limestone can be heated with clay to make cement
Cement is mixed with sand and water to make mortar
Cement is mixed with water, sand and crushed rock to produce concrete
Useful as a building material but is damaged by acid rain
When carbonates react with acids, carbon dioxide is given off as well as making a salt and water.

12. 1. Calcium carbonate  calcium oxide + carbon dioxide
Limestone reactions
1. Calcium carbonate  calcium oxide + carbon dioxide
CaCO3  CaO CO2
2. Calcium oxide + water  calcium hydroxide
Calcium hydroxide is an alkali ( Limewater). It can be used to neutralise acids. It is used by farmers to neutralise acidic soil, and to neutralise acidic industrial gases.
3. Calcium hydroxide + carbon dioxide  calcium
carbonate + water
This is the test for carbon dioxide.

13. Magnesium carbonate  magnesium oxide + carbon dioxide
Other Carbonates
The carbonates of magnesium, copper, zinc, calcium and sodium can be thermally decomposed too
They always form a metal oxide and carbon dioxide
Magnesium carbonate  magnesium oxide + carbon dioxide

14. Advantages of using limestone and producing building materials form it
Disadvantages
Can build houses and roads from it
Neutralise acidic soil
Neutralises sulphur dioxide in power station chimneys
Jobs for local people
Landscape can be restored after use
Makes the landscape ugly
Dust pollution
Sound pollution from blasting
Destroys animal habitats
To make cement needs energy which is got from burning fossil fuels- global warming

15. Advantages of limestone + its products over other materials
Disadvantages
Widely available
Cheaper than granite/marble
More hardwearing than marble
Concrete can be poured into moulds
Doesn’t rot like wood
Doesn’t corrode like metals
Can be reinforced with steel
Concrete is ugly looking
Concrete has a low tensile strength

16. Extracting metals Metals are found naturally in the Earth’s crust
They are often chemically combined with other elements – this is called the ore
Whether it is worth extracting a metal depends on:
1. How easy it is to extract it from its ore How much metal the ore contains

17. Extracting metals electrolysis carbon reduction Other methods
The way we extract a metal depends on its place in the reactivity series
Most reactive
Least reactive
Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Copper
Silver
Gold
Platinum
electrolysis
carbon reduction
Other methods

18. Copper
Pure copper is a good conductor of electricity, does not react with water and can be shaped easily
Copper can be removed from its ore by smelting
( heating in a furnace)
The copper produced is purified using electrolysis
This involves passing an electrical current through a copper solution
Metal ions are positive so pure copper forms at the negative electrode

19. Copper Copper-rich ores are running out
New methods are used to extract copper from low grade ores
Phytomining – using plants to extract copper
Bioleaching – using bacteria to extract copper
Scrap iron can be dipped into a solution of a copper salt to extract copper ( displacement)
Solutions can be electrolysed

20. Aluminium Aluminium is a very low density metal
Because it is higher than carbon in the reactivity series it is extracted using electrolysis
Electrolysis is very expensive because lots of energy is needed to get temperatures high enough to melt the ore and electricity is needed to split the ore
This is why we recycle aluminium

21. Titanium Titanium is very strong and has a very high melting point
It is used for replacement hip joints
It cannot be reduced using carbon because it is more reactive
It is reduced (using sodium or magnesium) but this process is very complicated and has lots of steps and large amounts of energy are needed which means the titanium is very expensive

22. Iron (III) oxide + carbon  iron + carbon dioxide
Iron ore contains iron combined with oxygen
Iron is extracted using carbon reduction
It is heated in a blast furnace
Iron (III) oxide + carbon  iron + carbon dioxide
Iron straight from the blast furnace still contains some impurities (it is about 96% iron) – it is very brittle and is called cast iron. It can be used to mould different shapes
Removing the impurities gives us pure iron – this is too soft for most uses

23. Iron To make iron stronger we can add small amounts of other elements
A metal that is mixed with other elements is called an alloy
Low carbon steel is easily shaped
High carbon steel is hard
Stainless steels are resistant to corrosion

24. Why recycle metals( or plastics)
Recycling does NOT involve using up valuable limited resources
Is cheaper than extraction due to needing less energy
NO MORE damage on the landscape
Stops filling up landfill sites

25. alloys Steel is an alloy of iron containing carbon
Alloys are harder than pure copper, gold iron and aluminium. The “added” atoms distort the layers

26. Crude oil
Crude oil is a mixture of a large number of compounds. They are NOT chemically combined together
We separate the different compounds by fractional distillation
This involves separating the different fractions depending on their boiling points

27. Fractional distillation of crude oil

28. Crude oil
Crude oil contains compounds made of only hydrogen and carbon – hydrocarbons
Most of the hydrocarbons are alkanes
The general formula for alkanes is CnH(2n+2)
Alkanes are saturated hydrocarbons because they only have single C-C bonds
Propane
C3H8

29. Monkeys Eat Peanut Butter
AlkAnes
Methane Ethane Propane Butane
Monkeys Eat Peanut Butter

30. e.g. Propane + oxygen  carbon dioxide + water
Combustion
When hydrocarbons are burned they react with oxygen(OXIDATION) & release energy
complete combustion – plenty of oxygen
e.g. Propane + oxygen  carbon dioxide + water
Incomplete combustion happens when there is not enough oxygen – carbon monoxide (CO) (a toxic gas) is produced instead of carbon dioxide

31. Products of combustion
Pollutant
Environmental problem
Sulphur dioxide
Acid rain
Oxides of nitrogen
Carbon dioxide
Global warming
particulates
Global dimming
Sulphur can be removed from the fuel before it is burned. Sulphur dioxide is removed from the waste gases before it is released e.g power stations

32. Cracking
After fractional distillation of crude oil, we are left with lots of less useful long-chain hydrocarbons
Long-chain hydrocarbons can be broken down into smaller ones by a process called cracking
This involves heating the fraction until it vapourises then passing it over steam or a hot catalyst
The products always include smaller alkanes( used as fuels) and alkenes

33. Hexane  butane + ethene
Cracking hexane
(800°C + hot catalyst)
Hexane  butane + ethene
C6H14  C4H10 + C2H4

34. Alkenes ( double “e” double bond)
Ethene
C2H4
Propene
C3H6
Butene
C4H8
Alkenes have the general formula CnH2n
Alkenes are Unsaturated as they have a double bond

35. Testing alkanes and alkenes
Bromine water reacts with alkenes and forms a colourless solution
Bromine water stays orange in alkanes

36. Biofuels
This includes biodiesel and ethanol which are made from plant material
They are made from renewable resources
Almost carbon neutral
But plant crop may be destroyed due to poor weather conditions
Using up land that should be growing crops to feed us

37. Polymers Alkenes molecules can be used to make plastics
Small molecules are called monomers
Lots of monomers joined together make polymers
monomers
polymer

38. A repeating unit of poly chloroethene (PVC)
Polymers n
A repeating unit of poly chloroethene (PVC)

39. New polymers New plastics with special properties are being developed
Dental fillings, waterproof fabrics and light sensitive plasters are made with special polymers
Smart polymers such as shape memory polymers ‘remember’ their original shape and will return to it when heated e.g. stitches closing a wound using body heat

40. Plastic waste
Many polymers are not biodegradable – this means microorganisms cannot break them down
New biodegradable polymers have been developed using starch and plant products that microorganisms can break down
This reduces the amount of plastics in landfills

41. Ethanol This is the type of alcohol found in alcoholic drinks
Its formula is C2H5OH
Ethanol can be made by fermentation of sugar from plants with yeast
Glucose (sugar)  ethanol + carbon dioxide
Ethanol can also be produced by reacting ethene (from cracking crude oil) with steam using a catalyst
Ethene + steam  ethanol

42. Vegetable oil
Some fruits, seeds and nuts are rich in oils that can be extracted
The plant material is crushed and the oil is removed by pressing or distillation
Vegetable oils provide nutrients and have a high energy content
Vegetable oils have higher boiling points than water so foods can be cooked at higher temperatures than by boiling
Food cooks faster and has different flavours
Food cooked in vegetable oil releases more energy when it is eaten but has a higher calorie content

43. Making Margarine
Most modern margarines are made from plant oils. The oil is heated and hydrogen is pumped through it. This is called hydrogenation
Vegetable oil + hydrogen → margarine
Some of the carbon-to-carbon double bonds in the plant oils are broken and extra hydrogen atoms are added. This hardens the oil to make it a solid at room temperature (its melting point has been raised..
This is useful as spreads or for use in cakes and pastries.
Nickel catalyst
60 C

44. Emulsions Oil does not mix with water
An emulsifier is a special molecule that can be used to mix them and stop them separating creating an emulsion
Emulsifiers work by having one end that dissolves in water (hydrophilic) and one that dissolves in oil (hydrophobic)
Emulsions include ice cream
and mayonnaise

45. Structure of the Earth Crust: thin Mantle: thickest section
Core: middle
The Earth is made up of many layers
The Earth is surrounded by the atmosphere

46. Where did the mountains come from?
Before Wegener developed his theory, it was thought that mountains formed because the Earth was cooling down, and in doing so contracted. This was believed to form wrinkles, or mountains, in the Earth’s crust. If the idea was correct, however, mountains would be spread evenly over the Earth's surface. We know this is not the case.

47. Alfred Wegener Continental drift.
Wegener proposed idea that the continents were all joined together at one time and slowly moved apart
His evidence included:
Jigsaw pattern of coastlines
Identical fossils and ages on the coasts of south America and Africa
Matching rock types and ages
But how did they move? He couldn’t explain it and many other scientists believed they were locked in place and maybe there were land bridges in the past that have now gone

48. Tectonic plates
The crust and mantle are broken up into large pieces (tectonic plates)
They move a few centimetres per year due to convection currents caused by radioactive reactions in the mantle
Earthquakes are caused when plate boundaries meet and push together, mountains are also formed here.

49. The modern atmosphere
The Earth’s atmosphere has been the same for about 200 million years

50. Air
Air is a mixture of gases with different boiling points. These can be separated out using fractional distillation

51. The early atmosphere
About 4.5 billion years ago when the Earth formed volcanoes released carbon dioxide, water vapour and small amounts of ammonia & methane – this formed the first atmosphere( similar to Venus and Mars)
As the Earth cooled the water vapour condensed, fell as rain & this formed the first oceans
When life evolved plants used the carbon dioxide & released oxygen during photosynthesis

52. How did it all begin( maybe)?
The Miller-Urey experiment simulated a lightning spark in a mixture of gases of the early atmosphere
A week later, more than 2% of the carbon in the system had formed compounds from which proteins in living cells are made

53. Carbon
Most of the carbon dioxide from the Earth’s early atmosphere has been taken up by plants, which were eaten by animals
This means that most of the carbon is ‘locked’ in sedimentary rocks and in fossil fuels
Carbon dioxide also dissolved in oceans
Over the past 200 million years the amount of carbon dioxide in the atmosphere has not changed much – however we are now burning fossil fuels and releasing carbon dioxide