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35 Cards in this Set
- Front
- Back
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Main constituent of natural gas |
Methane |
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Fractional distillation of petroleum |
Refinery gas - bottled gas for heating & cooking Gasoline - for fuel (petrol) in cars Naptha - Making chemicals Kerosene - Jet fuel Diesel Oil - Diesel in engines Fuel Oil - Fuel for ships and home heating systems Lubricating - Lubricants, waxes and polishes Bitumen - Making roads (BP Increase as you go down) |
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Homologous series |
A 'family' of similar compounds with similar properties due to the presence of the same functional group. |
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Characteristics |
-Same general formula -Same functional group -Similar chemical properties -Different chain lengths -Different physical properties due to increasing molecular size: M.P and B.P inc. Viscosity inc. Density inc. Flammability inc. |
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Structural isomers |
Compounds with the same general formula but different structural formula. Compounds with branched chains have lower BP |
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Alkanes |
CnH2n+2 -Form single C-C bonds -Saturated -Generally unreactive Except: -They burn in air -They react with chlorine (Under UV light) CH4 + Cl2 -> CH3Cl + HCl CH3Cl + Cl2 -> CH2Cl2 + HCl |
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Alkenes |
CnH2n -Have a double covalent bond C=C -Unsaturated -Reactive -Obtained from alkanes through cracking. -Cracking involves heating vaporized alkenes in the presence of catalyst |
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Alkene reacts with H2... |
To form an alkane (in 180C, using Nicket or Platinum) (Hydrogenation) |
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Alkene reacts with steam .... |
To form an alcohol (equilibrium reaction) Conditions: 570C, 60-70 atm, a catalyst (phosphoric acid) It's a hydration/addition reaction Exothermic 570 is a compromise |
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Addition Polymerisation |
Alkene molecules add on to each other in the presence of a catalyst |
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The alkene molecules in a polymer are called... |
Monomers |
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Alcohol |
CnH2n + 1 OH -Saturated |
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How is ethanol obtained |
C6H12O6 -(enzymes in yeast at 35C) -> 2C2H5OH + 2CO2 + energy |
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How ethanol is obtained in the fermentation of glucose |
The enzymes in yeast catalyse the breakdown of glucose into ethanol and carbon dioxide.-This is an exothermic reaction.-Ethanol is seperated by fractional distillation. |
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Hydration of ethene's properties |
-Releases a lot of heat energy -It is a good solvent. Dissolves many things that don't dissolve in water -It is flammable when burnt/heated -Used as a fuel. Burns readily in air to give plenty of heat |
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Carboxylic Acids |
CnH2nO2 |
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Ethanoic Acid |
Colourless liquid with very strong odour and taste. Weak acid |
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How ethanoic acid is obtained |
If ethanol is left standing in air, bacteria will bring about its oxidation This is called acid fermentation (vinegar is made this way) |
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How is ethanol oxidised |
By warming it with Potassium Manganate (Vlll), a powerful oxidising agent in the presence of acid The manganate (Vlll) ions are reduced to Mn2+ ions, with a colour change MnO4 (purple) + 8H (provided by acid) + 5e- -> Mn2+ (colourless) + 4H2O |
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Ethanoic acid reacts with alcohols to form esters |
Ethanoic acid + Butanol -> Butyl Ethanoate + Water -Ester linkage is O=C-O -Esters are used as artificial flavourings and fragrances |
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Macromolecules |
-Large molecules built up from small units, monomers -Different macromolecules have different units and/or different linkages |
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Addition Polymerisation VS Condensation Polymerisation |
-The polymerisation gives long-chain molecules - and no other product -The polymerisation gives long-chain molecules-and there is always one other product |
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Properties of Polyethene |
-Light -Bends without breaking -Tough -Water Resistant |
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PVC is... |
Poly(chloroethene) |
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Condensation Polymerisation |
-Monomers are two different molecules -Other product is a small molecule which is eliminated |
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Uses of plastics |
Water proof clothing, covering for electrical wiring, dustbins, tables and chairs, water pipes |
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Use of nylon |
Thread, ropes, fishing nets, carpets |
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Uses of terylene |
Can be drawn out into tough light, hard-wearing fibre that is easily woven |
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Non-biodegradable plastics' problems |
-Plastic bags are responsible for much of the litter seen everywhere -Plastic bags clog up drains and river beds, and help to cause flooding -If burned, many plastics release toxic gases -Fish, birds, and other animals get tangled in plastic waste. Can choke them. -When fish, birds and other animals swallow plastic, they can't digest it. But it fills their stomachs, and they die out of hunger. |
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Nylon/Terylene's linkages and small molecule eliminated |
-Diaminoalkene combines with Dioylchloride to form nylon (a polyamide) with an amide linkage, HCl is eliminated -Dicarboxylic acid combines with dialcohol to form terylene (a polyester) with an ester linkage, H2O is eliminated |
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Proteins |
-Proteins have same amide linkage as nylons but different units -During digestion the proteins in our food are hydrolysed back to amino acids (conditions: 6M of HCl for 24 hrs) -Amino acids join up again to make the proteins our body needs |
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Hydrolisis |
The breaking down of a compound by reaction with water |
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Fats |
-Have ester linkage just like Terylene but with different units. Result of hydrolysis in fats - glycerol + sodium salts of fatty acids (condition: with dilute NaOH) -The sodium salts of the fatty acids are used as soaps. |
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Carbohydrates |
-Complex carbs are made of large units of monosaccharides (like glucose) -Water molecules are eliminated Results of hydrolysis of carbs: Individual simple sugar units (condition: dilute HCl) (monosaccharides) |
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Alcohol can also be oxidised through... |
Acidified potassium dichromate (Vl) K2Cr2O7 Colour changes: orange to green |
