29/02/2016 Oils, Earth and Atmosphere The New Bridge Academy (AQA)

29/02/2016 Crude oil Revision Longer chains mean… 1.Less ability to flow 2.Less flammable 3.Less volatile 4.Higher boiling point Increasing length Crude oil is a mixture of HYDROCARBONS (compounds made up of carbon and hydrogen). Some examples: Ethane C C H H H HH H Butane CC H H H HH H C C H H H H

29/02/2016 Using Crude Oil BenefitsDrawbacks

29/02/2016 Using Crude Oil Crude Oil BenefitsDrawbacks Cheap to extract Wide range of uses as fuel Used to make plastics Plastics don’t biodegrade Burning fossil fuels causes pollution Disposal of materials uses up land fill sites

29/02/2016Ethanol Ethanol is an important chemical. Many countries are increasing the amount of ethanol put into their petrol supplies: Ethanol is a “clean burning” energy source and produces little or no greenhouse gases. How is it made? Ford Escape E85 – runs on 85% ethanol The “fossil fuel” way The “renewable” way Ethene + steam ethanol Ethene is produced by “cracking” oil Sugar ethanol + carbon dioxide Sugar is produced from standard crops like sugar cane and corn

29/02/2016Cracking Shorter chain hydrocarbons are in greater demand because they burn easier. They can be made from long chain hydrocarbons by “cracking”: Butane Ethane For example, this bond can be “cracked” to give these: Ethene

29/02/2016Cracking This is a THERMAL DECOMPOSITION reaction, with clay used as a catalyst 1)Carbon dioxide causes the _________ effect 2)Sulphur 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, sulphur dioxide and water vapour. There are three main environmental problems here: Long chain hydrocarbon Heated catalyst Liquid hydrocarbon Gaseous hydrocarbon

29/02/2016Alkenes Alkenes are different to alkanes; they contain DOUBLE COVALENT bonds. For example: Ethane Ethene Butane Butene This double bond means that alkenes have the potential to join with other molecules – this make them REACTIVE. They have the general formula C n H 2n ALKANES ALKENES

29/02/2016 Monomers and Polymers CC H H H H Ethene Here’s ethene again. Ethene is called a MONOMER because it is just one small molecule. We can use ethene to make plastics… Step 1: Break the double bond Step 2: Add the molecules together: This molecule is called POLYETHENE, and the process that made it is called POLYMERISATION

29/02/2016 Another way of drawing it… Instead of circles, let’s use letters… Ethene CC H H HH CC H H HH H C C H H H H C C H H H Poly(e)thene General formula for addition polymerisation: C C n C C n e.g. C C n H CH 3 H H C C n H H H

29/02/2016 Some examples C C n H H H H C C n H H H Cl C C n H H H H C C n H H H C C n H H Br C C n H Cl H Br

29/02/2016 Uses of addition polymers Poly(ethene)Poly(propene) Poly(chloroethene), PVCPoly(styrene)

29/02/2016 Disposal of plastics 1) Landfill sites - most plastics do not _________ which means that landfill sites are quickly filled up. Research is being carried out on __________ plastics. 2) Burning – this releases carbon dioxide which causes the ________ effect, as well as other ________ gases. 3) _______ – the best option, but difficult because of the different types of plastic Words – recycling, greenhouse, decompose, biodegradable, poisonous

29/02/2016 Vegetable Oils Use of oilBenefitsDrawbacks Oily foods Fuel When plants photosynthesise they produce glucose. They can also produce vegetable oils and we can use these for food and fuel:

29/02/2016 Extracting Oil Step 1: Crush the plant Step 2: Remove oil by pressing OR step 3: Remove oil by distillation

29/02/2016 Healthy and Unhealthy Oils Unhealthy oils: Healthy oils: “Saturated” “Unsaturated”

29/02/2016 Saturated vs. Unsaturated Fats Some oils are more healthy than others. Fish oils contain the nutrients Omega-3 and Omega- 6. These oils are “unsaturated” like ethene: CC H H H H Ethene Testing for double bonds: Clearly, it is important for scientists to be able to test if a food contains “healthy” unsaturated fats or “unhealthy” saturated fats. Here’s how it’s done: Oil (in ethanol) Bromine goes colourless Bromine water

29/02/2016 Turning unsaturates into saturates The unsaturated fat is hardened by “hydrogenation”. Hydrogenated oils have a higher melting point and so are solid at room temperature C, Nickel catalyst

29/02/2016 Artificial Additives Why do we use additives? Some examples: AdditiveInteresting information Flavour enhancersCan include traditional ingredients like salt, vinegar etc. Monosodium glutamate is often used in Chinese foods (its found in soy sauce) Colour enhancersProcessing food often results in colour loss so colour enhancers are used. Could be natural like carotenes or artificial like tartrazine PreservativesCan include vinegar and sugar. Artificial preservatives are used to stop microbes growing and antoxidants stop fats going off Vitamins and mineralsCan be used to replace those lost during cooking

29/02/2016 E numbers E100–E199 (colours) E200–E299 (preservatives) E300–E399 (antioxidants, acidity regulators) E400–E499 (thickeners, stabilizers, emulsifiers) E500–E599 (acidity regulators, anti-caking agents) E600–E699 (flavour enhancers) E900–E999 (miscellaneous) E1000–E1999 (additional chemicals) If artificial additives are “approved” they are given an E number:

29/02/2016Emulsions What’s an emulsion? It’s a mixture of oil and water, like in salad dressing… Paint is an emulsion. Other examples: MilkCreamButter Butterfat Watery liquid

29/02/2016 Why use emulsions? Emulsions can have varying textures and this makes them useful. Some examples: Different thicknesses of cream Paint and mayonnaise

29/02/2016 R G B XChromatography Chromatography can be used to separate a mixture of different inks. Some example questions… Z 1) Ink X contains two different colours. What are they? 2) Which ink is ink Z made out of?

29/02/2016Chromatography Chromatography can be used to test which foods contain which ingredients. For example, consider the dye Sudan 1, which was found in 450 foods in 2005: Sudan 1 Dye 1 Dye 2 Dye 3

29/02/2016 The Structure of the Earth A thin crust km thick A mantle – has the properties of a solid but it can also flow A core – made of molten nickel and iron. Outer part is liquid and inner part is solid The average density of the Earth is much higher than the crust, so the inner core must be very dense

29/02/2016 Movement of the Lithosphere The Earth’s LITHOSPHERE (i.e. the _______) is split up into different sections called ________ plates: These plates are moving apart from each other a few centimetres every _______ due to the ________ currents in the mantle caused by the ________ decay of rocks inside the core. Words – radioactive, crust, convection, tectonic, year

29/02/2016 Forming new crust Magma Earthquakes and volcanic eruptions can be common here

29/02/2016 Continental Drift Look at the coastlines of South America and Africa. I wonder of they used to fit together… Alfred Wegener

29/02/2016 Tectonic theory People once thought that the oceans and the continents were formed by shrinkage from when the Earth cooled down after being formed. Alfred Wegener proposed something different. People didn’t believe him because he couldn’t prove it, so he had to find some evidence: These continents look like they “fit” together. They also have similar rock patterns and fossil records. These are the two pieces of evidence that led me to believe that there was once a single land mass. This is my TECTONIC THEORY.

29/02/2016 Forming mountains The formation of mountain ranges can be explained by tectonic theory. Consider the Himalayas at the top of India: This is where India is now This is where India was millions of years ago The intense heat and pressure from this process causes the rocks to change structure into metamorphic rocks.

29/02/2016 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 The Evidence: 1)Some continents look like they used to “fit” together 2)Similar rock patterns and fossil records The Problems: Wegener couldn't explain how continental drift happened so nobody believed him Conclusion – scientists now believe Wegener’s Tectonic Theory

29/02/ Billion years3 Billion years2 Billion years1 Billion yearsPresent day Evolution of the Earth’s Atmosphere Carbon dioxide MethaneAmmoniaOxygenNitrogenOthers Present day atmosphere contains 78% nitrogen, 21% oxygen, 1% noble gases and about 0.03% CO 2

29/02/2016 Group 0 – The Noble gases He Ne Ar Kr Xe Rn

29/02/2016 Group 0 – The Noble gases 3) Helium is less _____ than air and is used in balloons and airships (as well as for talking in a silly voice) 4) Argon is used in light bulbs (because it is so unreactive) and argon, krypton and ____ are used in fancy lights Words – neon, dense, unreactive, helium Some facts about the noble gases: 1)They include neon, argon and ___________ 2)They are all very ________

29/02/ Billion years3 Billion years2 Billion years1 Billion yearsPresent day Evolution of the Earth’s Atmosphere Volcanic activity releases CO 2, methane, ammonia and water vapour into the atmosphere. The water vapour condenses to form oceans. Some of the oxygen is converted into ozone. The ozone layer blocks out harmful ultra-violet rays which allows for the development of new life. Green plants evolve which take in CO 2 and give out oxygen. Carbon from CO 2 becomes locked up in sedimentary rocks as carbonates and fossil fuels. Methane and ammonia react with the oxygen and nitrogen is released. Nitrogen is also produced as a result of denitrifying bacteria on nitrates from decaying plants.

29/02/2016 Carbon dioxide in the atmosphere The amount of CO 2 in the atmosphere is affected by 3 things: 1) Geological activity moves carbonate rocks deep into the Earth and they release ______ _______ into the atmosphere during volcanic activity. 2) When fossil fuels are burned the carbon contained in them reacts with _____ to form CO 2. 3) Increased CO 2 in the atmosphere causes a reaction between it and _______. These reactions produce two things: INSOLUBLE CARBONATES (which are deposited as ______) and SOLUBLE HYDROGENCARBONATES (which ________ in the seawater). These reactions do not remove ALL of the new CO 2 so the greenhouse effect is still getting _______! Words – oxygen, seawater, carbon dioxide, worse, dissolve, sediment