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FlashCards por WholcokedOtaku, atualizado more than 1 year ago
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Criado por WholcokedOtaku
mais de 9 anos atrás
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| Questão | Responda |
| Distillation | Is used to separate the components in a mixture of liquid which have different boiling points. E.g A mixture of ethanol (b.p 78) and water (b.p 100) |
| Fractional Distillation | Used when the components in a mixture have very similar boiling points. |
| Fraction | Is a mixture of hydrocarbons of similar Carbon Chain length. |
| Crude oil | Mixture of many different hydrocarbons. |
| Hydrocarbons | Compounds made up of Hydrogen and Carbon only. |
| Crude oil seperation | Different fractions have different boiling points and this property is used to separate fractions from crude oil. |
| Fractional Distillation column | |
| Alkanes | Saturated (Maximum possible hydrocarbons) Hydrocarbons (compounds of carbon and hydrogen) No Carbon-Carbon double bond General formula= CnH2n+2 Carbon makes 4 bonds Hydrogen makes 1 bond |
| General Alkanes | h Methane= CH4 h c h h Ethane=C2H6 Propane=C3H8 Butane=C4H10 Pentane=C5H12 |
| Distillation Properties | Flammability Viscosity(Thickness) Size of Carbon Chains |
| Burning Fuels | Hydrocarbon + Oxygen -> Carbon Dioxide + Water Coal + Impurities of Sulphur + Oxygen -> CO2 +H2O + Sulphur Dioxide Hydrocarbon + Insufficient O2 -> Carbon Monoxide + H2O |
| Pollutants | CO2 = Global Warming Carbon Monoxide= Poisonous Sulphur Dioxide= Acid Rain Nitrogen oxide= Acid Rain + Triggers asthma Carbon Particulates(small particles of carbon)= Smog/smoke/fog -> poor visibility |
| Alternative fuels | Hydrogen Ethanol Biodiesel |
| Using Hydrogen as a fuel | Production= Electrolysis of water 2H2O -> 2H2 +O2 OR Using Methane= Methane + Steam-> Carbon monoxide + Hydrogen Burning hydrogen= H2+O2 -> H20 |
| Advantages of using Hydrogen as a fuel | Only water vapours are produced when burnt. |
| Disadvantages of using Hydrogen as a fuel | Formation of Hydrogen produces a poisonous gas (Methane production). Electrolysis of water needs electricity. Can explode as it is highly flammable. H2 is a gas, so storage is a problem as it needs low temperature, but high pressure. |
| Using Ethanol as a fuel | An Alcohol. Production of ethanol= Glucose(sugarcane) ->(yeast and 37C) Ethanol +CO2 C6H12O6 -> C2H5OH +CO2 |
| Advantages of using Ethanol as a fuel | Renewable Carbon neutral fuel.(?) |
| Disadvantages of using ethanol as a fuel | Burning Ethanol produces CO2. Quite flammable. Shortage of land-shortage of food crops-starvation. |
| Bio-diesel | A fuel produced from plant sources. |
| Production of bio-desiel | |
| Combustion | Hydrocarbon + Oxygen -> Carbon dioxide + Water Hydrocarbon = (Insufficient) Oxygen -> Carbon monoxide + Water + Carbon Sulphur + Hydrocarbon + Oxygen -> Carbon dioxide + Sulphur dioxide + Water Nitrogen + Oxygen -> (High Temperature) Nitrogen oxide |
| (Catalytic) Cracking | The process where larger, less useful hydrocarbons are broken into smaller and more useful molecules, using heat and a catalyst. An example of Thermal Decompostion. |
| An example of Cracking | Octane -> Ethene + Hexane (Heated to 800C with AL2O3 or Aluminum oxide/Alumina) h h C8H18 -> C=C h h + C6H14 |
| Definition of Catalyst | A substance which speeds up the reaction without being used up within the reaction. |
| Alkenes | Unsaturated Hydrocarbons Unsaturated means in the molecule there is at least ONE carbon-carbon double bond present e.g C=C |
| General Formula for Alkenes | CnH2n |
| Bromine Water and Alkenes/Alkanes | Bromine water starts of yellow/orange Bromine water stays the same colour in the presence of an ALKANE Bromine water goes colourless in the presence of an ALKENE. |
| Demand for ALKANES | Shorter alkanes are more in demand than longer alkanes because they are used as fuel/easier to ignite A fraction of crude oil that has more demand than what meets supply is petrol. One fraction of crude oil that is in greater supply than demand is fuel oil. |
| Products made from cracking | Alkanes= Fuels Alkenes= Plastics |
| Polymers | Plastics are long chained molecules (1000s of atoms) Long chained molecules are called polymers which are formed by joining small molecules called monomers. Formed when many monomers join together- reaction called addition polymerisation |
| Monomers | Small molecules At least ONE carbon-carbon double bond. |
| Polymer formula | h h n C=C h h -> (h h) (C=C) ( h h) |
| Polymer examples | Propene -> Polypropene Styrene -> Polystyrene Vinylchloride -> Polyvinylchloride |
| Designer Polymers | Polymers that have been designer for different uses. |
| Shape memory polymer | A polymer that changes shape as the temperature changes. Useful for braces. |
| Hydrogels | Polymers that work by when the sodium particulates are taken away, the polymer uncoils and the water molecules are attracted to the uncoiled chains. Useful for nappies |
| Dental polymers | Polymers that when UV light is shone on them, they paste together. Better than metal fillings as they don't conduct heat, and they paste together to make a solid filling. Useful for fillings |
| Polymer developments | 1. Food packaging that changes colour when food goes off. 2. Anti-microbial chemicals in packaging to extend shelf life. |
| PTFE | Breathable fabric- allow water from sweat to escape. Work- three layers, outer, PTFE, inner. Outer layer gets wet. PTFE- small holes to allow water vapour through, but not water droplets. |
| Disposing of plastics | Burning polymers Burying plastics Exporting plastic Re-using plastic Reducing plastic Recycling plastic Bio-degradable plastic |
| Burning plastics | adv- can be used to generate electricity dis- plastics give off toxic fumes when burnt |
| Burying plastics | Does not biodegrade. |
| Exporting plastic | Places such as New York have run out of room in landfill- export out of the state to get rid off their plastic,- somewhere else has to deal with it. |
| Re-using plastic | adv- easy to do dis- most plastic is used for packaging, and thus a one off use. |
| Reducing plastic use | Some foods can be used to make packaging. Paper bags. Wrapping food in greaseproof paper rather than cling film. |
| Types of plastic (main types) | 1.PETE poly(ethene)terephthalate 2. HDPE High density poly(ethene) 3. PVC Poly Vinyl Chloride 4. LDPE Low density poly(ethene) 5. PP Poly(propene) 6. PS Polysterene |
| Biodegradable plastics | Scientists use biotechnology to change genes in potatoes, so they make plastic instead of starch. |
| Ethanol | C2H5OH |
| Uses of ethanol | 1. Biofuel 2. Alcoholic drinks 3. Hand gel, aftershave, perfumes (low boiling point) 4. Disinfectant in hospital hand gel |
| Making ethanol (Fermentation of carbohydrate) | Fermentation of plant source C6H12O6 ->(yeast) CO2 + C2H5OH 37C (35C-40C) Normal (low) pressure Yeast catalyst Absence of oxygen+water Batch process (stop/start-labour intensive) Slow reaction + impure ethanol Sustainable Carbon neutral |
| Making ethanol (Ethane + steam) | Crude oil CH2 = CH2 +H2O -> C2H5OH 300C 60-80 atm (pressure) Phosphoric acid as a catalyst Continuous process Fast reaction rate Pure ethanol Not sustainable Energy is needed and uses non renewable resources |
| Extraction of plant oils Crushing | 1. Seeds/plant material is crushed. 2. Oil is removed via pressing. 3. Unrefined oil with impurities. 4. Impurities removed. 5. Refined oil obtained. |
| Extraction of plant oils Boiling | 1. Plants put in boiling water. 2. Oil evaporates from plants. 3. Collected by condensing it. 4. Water and impurities removed for pure oil. |
| Types of oils | Saturated oils Monounsaturated oils Polyunsaturated oils |
| Saturated oils | Only carbon-carbon SINGLE bonds present NO carbon-carbon double bonds |
| Monounsaturated oils | Only ONE carbon-carbon DOUBLE bond present |
| Polyunsaturated oils | Many Carbon-Carbon DOUBLE bonds present. "Healthy" oil. |
| Detection of unsaturation | Bromine water- Yellow Br2 turns colourless Iodine water -Brown I2 water turns colourless n.b mor unsaturation in the molecules, the more Br2/I2 water will be needed. |
| Saturated oil/fat | Solid at room temperature High melting point Mainly present in animals Unhealthy |
| Unsaturated oil/fat | Liquid at room temperature (usually) Low boiling point Plant oils are mostly unsaturated Healthy |
| Hydrogenation/hardening of oil | Number of Carbon-Carbon double bonds are reduced by reacting vegetable oil with hydrogen in the presence of a catalyst. Useful- making margarine form sunflower oil and spreads. |
| Emulsions | Formed when droplets of one liquid (i.e oil) are suspended in another liquid (i.e water) |
| Water and oil | DO NOT MIX Water is polar, oil is nonpolar Water molecule- small Oil molecule- large |
| Immiscible | Two liquids that DO NOT MIX |
| Miscible | Two liquids that MIX |
| Emulsifier | The molecule that slows the time taken for the immiscible liquids to seperate |
| Formation of an emulsion Oil and water | Emulsifier's hydrophobic tail binds with oil, hydrophilic head binds with water. Charged droplets repel each other- spread apart in water. Small droplets collide + form bigger droplets. Mixture separates and two layers form. Emulsion with emulsifier takes longer to separate. |
| Earth's structure | asdfghjkl; |
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