1. 09/03/2016 Chemistry 1

2. 09/03/2016 The structure of the atom Electrons in shells Proton in nucleus Neutron in nucleus

3. 09/03/2016 Mass and atomic number ParticleRelative MassRelative Charge Proton1+1 Neutron10 ElectronAlmost 0 MASS NUMBER = number of protons + number of neutrons SYMBOL PROTON (ATOMIC) NUMBER = number of protons (or electrons)

4. 09/03/2016Symbols Elements are represented by symbols

5. Elements, compounds & mixtures 09/03/2016 Elements – contain one type of atoms Mixtures – two or more elements not chemically joined Compounds – two or more elements chemically joined

6. 09/03/2016 Mendeleev Periodic table FrRaCsBaLaHfTaWReOsIrPtAuHgTlPbBiPoAtRnRbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXeKCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKrNaMgAlSiPSClArLiBeBCNOFNeH He Reactive metals Transition metals Other metals Non-metals Noble gases Separates metals and non-metals Columns called groups Rows called periods

7. 09/03/2016 Electron structure Potassium has 19 electrons. These electrons occupy specific energy levels “shells”… Nucleus The inner shell has 2 electrons The next shell has 8 electrons The next shell has the remaining 1 electron Electron configuration = 2.8.8.1

8. 09/03/2016Compounds Compounds are formed when two or more elements are chemically combined. Some examples: Glucose Methane Sodium chloride (salt)

9. 09/03/2016 Covalent bonding Hydrogen has just 1 electron in its outer shell. A full (inner) shell would have 2 electrons, so two hydrogen atoms get together and “share ” their electrons: Now they both have a full outer shell and are more stable. The formula for this molecule is H 2. Atoms sharing electrons is called covalent BONDING. This bonding occurs between non- metals atoms. Each atom make enough covalent bonds to fill it’s outer shell

10. 09/03/2016 Ionic bonding Na + This is where a metal bonds with a non-metal. Electrons are transferred between atoms. Metal atoms lose electrons to form positive ions Non-metals gain electrons to form negative ions Sodium in Group 1 has 1 electron on its outer shell Chlorine in Group 7 has 7 electrons in outer shell. Sodium transfers 1 electron – so both atoms have a full outer shell and are stable. Positive and negative charges attract A positively charged sodium ion A negatively charged chloride ion Cl -

11. 09/03/2016Limestone Limestone is a sedimentary rock made up of mainly calcium carbonate. It’s cheap and easy to obtain by quarrying. Uses  Building materials  Making cement. CaCO 3 heated with clay  Making mortar. Cement mixed with sand and water  Making concrete. Cement mixed with sand and aggregate  Neutralising acidic soil & lakes - slaked lime

12. Limestone Positives of quarrying Provides jobs Provides materials Provides neutralisation products Negatives of quarrying Destroys habitats Produces noise and dust Transportations makes pollution Destroys landscape 09/03/2016

13. The “Limestone Cycle” Calcium Carbonate (CaCO 3 ) calcium oxide + carbon dioxide CaO (quicklime) + CO 2 calcium hydroxide Ca(OH) 2 (slaked lime) Step 1: CaCO 3 heated – thermal decomposition Step 2: add water to quicklime Step 3: add carbon dioxide to slaked lime + water

14. Metal extraction 09/03/2016 Metals can either be found native in the ground (e.g. gold) or are found as metal ores (e.g. iron = haematite, aluminium = bauxite) Metals  above carbon extracted by electrolysis  below carbon extracted by reduction  silver and gold found native increasing reactivity potassium sodium calcium magnesium aluminium carbon zinc iron lead copper silver gold

15. Reduction 09/03/2016 Reduction is the removal of oxygen The metal ore is reacted with carbon. The carbon is more reactive so removes the oxygen from the ore iron oxide + carbon  carbon dioxide + iron carbon zinc iron lead copper

16. ++++++++ --------Electrolysis 09/03/2016 Electrolysis is breaking down a substance using electricity It needs a liquid to conduct electricity. High temperatures are needed, which needs a lot of energy making it expensive potassium sodium calcium magnesium aluminium carbon Solution containing copper ions Negative electrode made of pure copper – gains Cu 2+ ions = grows Positive electrode made of impure copper – loses Cu 2+ ions = shrinks Cu 2+

17. Bioleaching & phytomining 09/03/2016 New mining techniques used to extract copper and decrease the effects of metal extraction on the environment. Bioleaching uses bacteria to separate copper from copper sulphide. The solution produced (leachate) contains copper which can be filtered. Phytomining uses plants grown in soil containing copper, which builds up in leaves. Leaves burnt and copper in ash can be collected.

18. Recycling metals Fossil fuels running out Recycling uses less energy than mining Recycling saves money Recycling cuts down on landfill sites Recycling reduces amount of pollution

19. 09/03/2016 FrRa CsBaLaHfTaWReOsIrPtAuHgTlPbBiPoAtRn RbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXe KCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKr NaMgAl LiBe Properties of metals Strong Can be bent Can be hammered Good conductors of heat and electricity

20. 09/03/2016 Copper, Aluminium and Titanium MetalPropertiesUses Copper Good electrical conductor, hard, strong, can be bent, doesn’t react with water Electrical wires, plumbing pipes and tanks Aluminium Corrosion resistant, low density, forms hard alloys Aeroplanes Titanium Low density, very strong, corrosion resistant Hip replacements

21. 09/03/2016Alloys An “alloy” is a mixture of metals. Alloys are harder than pure metals Gold mixed with copper Aluminium mixed with magnesium and copper Aluminiun mixed with chromium

22. 09/03/2016 Using Iron Iron produced by the blast furnace contains about 96% iron and 4% impurities. These impurities make it very brittle and easy to break. Iron is alloyed to make steel. Steel with a low carbon content is easily shaped Steel with a high carbon content is strong but brittle Steel with chromium and nickel is called stainless steel

23. Crude oil 09/03/2016 Crude oil is a mixture of hydrocarbons (only contains elements hydrogen and carbon) The separate parts – fractions – can be extracted by fractionating distillation Crude oil piped in at bottom of fractionating column, heated, oil evaporates and rises. Fractions condense and are collected DecreasingtemperatureDecreasingtemperature

24. 09/03/2016Alkanes Alkanes are saturated hydrocarbons - all of the atoms are held together by single bonds. General formula is C n H 2n+2 - twice as many hydrogen atoms as carbon atoms plus an extra two Methane – CH 4 Ethane – C 2 H 6 Propane – C 3 H 8 Butane – C 4 H 10

25. 09/03/2016Patterns Longer chains mean… 1.More viscous (gloopy) 2.Less flammable 3.Higher boiling point Increasing length

26. 09/03/2016Fuels A fuel is burned to release energy Coal, oil and gas are fossil fuels.

27. 09/03/2016 Burning Fossil Fuels Burning fossil fuels (combustion) releases gases and particles C H H H H O O O O O H H O H H C O O Complete combustion (plenty of oxygen) produces carbon dioxide and water Carbon dioxide is a “greenhouse gas” – cause global warming Incomplete combustion (not enough of oxygen) produces carbon monoxide and carbon O O C H H H H C O Carbon monoxide is a poisonous gas

28. Sulphur dioxide 09/03/2016 Burning coal releases sulphur dioxide and nitrogen oxides Sulphur dioxide and nitrogen oxides cause acid rain and “global dimming” – sunlight is absorbed by the particles in the atmosphere. Acid rain kills trees, causes lakes to become acidic killing wildlife and damage limestone buildigns and statues

29. Alternative fuels 09/03/2016 FuelProsCons Ethanol – made from plant material Carbon neutral – CO2 used for plant to grow. Other waste product is water Engines need to be converted. Isn’t widely available yet. Biodiesel – made from vegetable oils Carbon neutral. Engines don’t need to be converted. Produces less SO 2 Expensive to make, would increase food prices Hydrogen gas – made from water Very clean – no pollution Need special, expensive engines. Isn’t widely available. Need to use energy to make it.

30. 09/03/2016Cracking Useful short chain hydrocarbons can be made from long chain hydrocarbons by “cracking”: Long chain hydrocarbon Heated catalyst Liquid hydrocarbon Gaseous hydrocarbon Long chain hydrocarbon heated to thermally decompose. Hydrocarbon vaporises, passes over a catalyst and splits into an alkane and an alkene

31. 09/03/2016Alkenes Alkenes are unsaturated hydrocarbons – there is a double bond between 2 carbon atoms. General formula is C n H 2n - twice as many hydrogen atoms as carbon atoms Ethene – C 2 H 4 Propene – C 3 H 6 Butene – C 4 H 8

32. Testing for alkenes 09/03/2016 Unsaturated alkeneColourless bromine water Orange bromine water

33. Making ethanol 1)Ethene reacted with steam in presence of catalyst. Ethene comes from crude oil – will eventually run out 2)Sugar fermented with yeast. Carbon dioxide also produced. Sugar grown - renewable 09/03/2016

34. Monomers and Polymers Alkenes can be used to make polymers (plastics) Lots of small alkene molecules – monomers – are joined together to make very large molecules – polymers Ethene  poly(ethene) Propene  poly(propene) C C n CC n EthenePoly(ethene)

35. 09/03/2016 Properties & uses of polymers Light and stretchy – used for plastic bags Elastic – used to make Lycra Waterproof – fabric coating Non-biodegradable – don’t rot

36. Extracting plant oils Extracted from fruits and seeds Plant material is crushed, pressed and filtered to remove impurities 09/03/2016

37. Emulsions 09/03/2016 Emulsions are a mixture of oil and water. Droplets of one liquid are suspended in the other liquid. Emulsions are thicker and have lots of uses – mayonnaise, ice cream and paint are examples Emulsifiers stop emulsions from separating – e.g. egg yolk

38. Emulsifiers - HT 09/03/2016 Emulsifiers have a water oil emulsifier hydrophilic (likes water, hates oil) part hydrophobic (likes oil, hates water) part.

39. Saturated and unsaturated oils 09/03/2016 Vegetable oils are unsaturated. They have a carbon-carbon double bond. Tested for bromine water

40. Hydrogenating oil- HT Unsaturated vegetable oil can be hardened by reacting them with hydrogen in the presence of a nickel catalyst at 60oC. Hydrogen adds to the carbon-carbon double bond. Hydrogenated oils have higher melting points = solid at room temperature. Useful for cakes and pastries 09/03/2016

41. The Structure of the Earth Thin crust - 10-100km thick Mantle – has properties of a solid but it can also flow Core – made of molten nickel and iron. Outer part is liquid and inner part is solid

42. 09/03/2016 Tectonic plates The Earth’s crust is split up into tectonic plates: These plates are moving apart from each other a few centimetres every year due to convection currents in the mantle caused by the radioactive decay of rocks inside the core.

43. 09/03/2016 Tectonic theory It was once thought that the oceans and the continents were formed by shrinkage from when the Earth cooled down after being formed. Alfred Wegener proposed that there was once a single land mass, that has changed as tectonic plates moved - TECTONIC THEORY. The evidence he had was  the continents look like they “fit” together.  had similar rock patterns and fossil records.

44. 09/03/2016 The Answer: 1)Scientists discovered 50 years later that the Earth generates massive amounts of heat through radioactive decay in the core. This heat generated convection currents in the mantle causing the crust to move 2)We also now know that the sea floor is spreading outwards from plate boundaries Tectonic theory Wegener couldn't explain how continental drift happened so nobody believed him

45. 09/03/2016 Movement at boundaries Movement of plate boundaries can be sudden and disastrous. Earthquakes and volcanoes happen at the boundaries between tectonic plates

46. 09/03/2016 4 Billion years3 Billion years2 Billion years1 Billion yearsPresent day Evolution of the Earth’s Atmosphere Carbon dioxide MethaneAmmoniaOxygenNitrogenOthers Present day atmosphere = 78% N, 21% O 2, 1% noble gases and about 0.03% CO 2 Phase 1 – volcanoes give out CO 2, H 2 O, CH 4 & NH 4. Water vapour and carbon dioxide condensed to form oceans Phase 2 – green plants evolved, using up CO 2 and producing O 2.