Cracking - converting large chain alkane molecules into smaller alkene and alkane molecules What is needed - 600 degrees heat Catalyst of alumina or silica Why - fractions with high boiling points don’t flow easily and are difficult to ignite Useful products - cracking produces alkenes for polymers Produces petrol Helps match supply and demand Fractional distillation - the process of moving crude oil into different groups Crude oil is a fossil fuel and is a finite resource - it contains lots of hydrocarbons of different size Hydrocarbon only contains hydrogen and carbon molecules Crude oil is mostly made out of alkanes A homologous series Same general formula Saturated Name ends in ane Fractions <0 degrees lower temperature LPG 20 - 200 degrees Petrol 180 - 260 degrees Paraffin Diesel 260 - 340 degrees Heating oil Heavy fuel oil >330 degrees Bitumen higher temperature size , intermolecular forces and boiling point all increase down the column - there is a temperature gradient - crude oil contains a range of different molecules/hydrocarbons - these hydrocarbons have different boiling points - hydrocarbons with different boiling points condense at different heights - larger molecules have higher boiling points because they have greater intermolecular bonding Life cycle assessment Cradle Use Grave CRADLE Raw materials required Other materials used to make the product Energy used in manufacturing process Water used in manufacturing process Environmental impact USE Energy needed to use the product Energy needed to maintain the product Environmental impact GRAVE Energy needed to dispose of the product Environmental impact of disposing product Extracting metals Ores that contain metals Chalcopyrite Bornite Azurite Chrysocolla Malachite Cuprite copper Drinking water Potable water = water that is safe to drink Salt water Contains large amounts of dissolved salt Must be removed by desalination Small scale desalination uses osmosis Large scale uses simple distillation Safe water method Reservoir Screens Settlement tank Aluminium sulfate and lime Fine sand filter Chlorine added Water stored Chlorine added to remove bacteria Global warming Sun radiation reaches earth Radiation warms up earth Infrared radiation emitted by earth surface - some go into space - some absorbed by greenhouse gasses Greenhouse gas emits radiation in all directions - warming up the earth Enhanced greenhouse effect What humans do that lead to global warming - carbon dioxide and methane Effects on climate change Rising sea levels Ice cap melting Altered weather patterns Pollution in the atmosphere Carbon dioxide - CO - petrol and diesel - burning coal and gas - toxic effect Sulphur dioxide - SO2 - petrol and diesel - burning coal and gas - acid rain and damage to plants Nitrogen oxides - NOx - petrol and diesel - burning coal and gas - toxic and acid rain Carbon - C - petrol and diesel - burning coal and gas - harmful if breathed in and acidic Air and the atmosphere 4.5 billion years ago - early earth was molten - any atmosphere was burned away 4 billion years ago - volcanic activity produces carbon dioxide and water vapour 2 billion years ago - the earth was cooled and oceans were formed 1 billion years ago - plants evolved and carried out photosynthesis - produced oxygen , used up carbon dioxide 5 years ago - carbon dioxide gets locked away Atmosphere today = 78% nitrogen 21% oxygen 1% other gases 1. Volcanic activity produced an atmosphere of carbon dioxide, water vapour, methane and ammonia. (Degassing from the Earths crust) 2. Earth cools and water fell as rain resulting in the formation of the oceans. 3. Photosynthetic organisms began to produce oxygen and use up carbon dioxide 4. Carbon dioxide locked up in the earth 5 Ammonia was changed in the soil into nitrogen gas 6. The atmosphere today contains nitrogen, oxygen and small amounts of carbon dioxide Aluminium extraction Aluminium exists as Aluminium Oxide Al2O3 in an ore called Bauxite Electrolysis is used to extract Aluminium The Aluminium Oxide has to be in molten from Aluminium Oxide has a mp of 2000oC Would be expensive to heat Instead it is dissolved in molten Cryolite Reduces the mp to 950oC Oxidation is loss Is Loss Reduction Is Gain