Organic Chem

Separated using fractional Distillation. Fractionating column Petroleum gas (Used as fuel for cooking and heating) Petrol (Used as fuel for car engine) Naphtha (Used as feedstock for chemical industry) Kerosene (Used as fuel for air-craft) Diesel (Used as fuel for diesel engine) Lubricating oil (Used to make wax and shoe polish) Bitumen (Used to pave road surface) Alkane Alkene Alcohol (liquid) Carboxylic acid (liquid) General formula CnH2n+2 CnH2n CnH2n+1OH CnH2n+1COOH Functional group C-C C=C -O-H -COOH First 4 members 1C : Methane (CH4 GAS) 2C : Ethane (C2H6 GAS) 3C : Propane (C3H8 GAS) 4C : Butane (C4H10 GAS) 2C: Ethene (C2H4 GAS) 3C : Propene (C3H6 GAS) 4C : Butene (C4H8 GAS) 1C : Methanol (CH3OH) 2C : Ethanol (C2H5OH) 3C : Propanol (C3H7OH) 4C : Butanol (C4H9OH) 1C : Methanoic acid (HCOOH) 2C : Ethanoic acid (CH3COOH) 3C : Propanoic acid (C2H5COOH) 4C : Butanoic acid (C3H7COOH) Isomer Compound with same molecular formula but different structural formula. Lowest boiling point (Smallest molecular mass) Highest boiling point (Largest molecular mass) Introduction to organic chemistry Homologous series: A family of organic compounds with same general formula and similar chemical properties. Members in the same homologous series 1. Has same functional group, general formula and similar chemical properties *Functional group : An atom or group of atoms that gives a molecule its characteristic properties. 2. Has a gradual change in their physical properties up the series ( Mp/bp ↑, density ↑, viscosity ↑, flammability ↓) 3. Differs from the next by a –CH2- unit. Fuel: Substance that burns exothermically. 3 main fossil fuel Coal Petroleum Natural gas Component Carbon Mixture of hydrocarbons of different size CH4 Amount of soot, CO and SO2 produced when burned A lot Moderate little 1. Petroleum is BOILED into VAPOUR in a furnace. ↓ 2. The vapour is PUMPED into a huge fractionating column which is cool at the top but hot at the bottom. ↓ 3. Hot vapour rises up the column and begins to cool down and condense. ↓ 4. Smaller hydrocarbon has lower boiling point and collected at the top column. ↓ 5. Larger hydrocarbon has higher boiling point and collected at the bottom column.

Reaction Equation Condition Application Alkane (Saturated) Combustion Complete: Alkane + O2  CO2 + H2O Incomplete : Alkane + O2  CO + H2O (soot might be formed) Substitution Methane + Cl2  chloromethane + HCl CH4 (g) + Cl2 (g)  CH3 Cl (g) + HCl (g) UV light Cracking Long alkane  Small alkane + small alkene + H2 C10H22  2C4H8 + C2H6 *Total number of C and H atoms in products must be same as those in reactants. Catalyst Al2O3 & SiO2 (Broken porous/china pot), high temperature, more than 600oC To meet the high demand of small alkanes that are used as fuel. Alkene (Unsaturated) Combustion Complete: Alkene + O2  CO2 + H2O Incomplete: Alkene + O2  CO + H2O *Alkene is less flammable than alkane due to higher % of carbon A d d i t i o n H2 (hydrogenation) Alkene + H2  Alkane Nickel catalyst, 200°C To convert vegetable oil (alkene) into margarine (alkane) Br2 (Bromination) Alkene + Br2  Dibromoalkane Room temperature TEST for alkene!!! Reddish- brown aqueous Br2 will turn colourless immediately if alkene is present. H2O (Hydration) Alkene + steam  Alcohol 300oC, 65 atm, Phosphoric (v) acid, H3PO4 as catalyst Addition polymerisation n (monomer)  polymer n (ethene)  (ethene)n Ethene  poly(ethene) n To make plastic water bucket, cling film etc. *Disadvantage of plastic: Non- biodegradable, takes up landfill site H H - C- C - H H I I I I n H H C=C H H I I I I Alkane and Alkene (Hydrocarbon)

Reaction Equation Condition Application/remarks Alcohol Combustion Alcohol + O2  CO2 + H2O Advantages of ethanol as fuel -Clean fuel (Little carbon monoxide or soot is formed) -carbon neutral fuel (no ↑ in the amount of CO2 in air when burnt) -Renewable fuel Oxidation Alcohol + [O]  Carboxylic acid + H2O Eg: Propanol + [O]  Propanoic acid + H2O * Test for alcohol Acidified potassium manganate (VII) (KMnO4), heat under reflux Oxygen gas in the presence of bacteria can oxidize alcohol too Note: KMnO4 can be used to test for alcohol Fermentation yeast Glucose  Ethanol + carbon dioxide C6H12O6  2C2H5OH + 2CO2 -37°C -Yeast -Absence of oxygen gas to prevent the oxidation of ethanol into ethanoic acid by the oxygen. Disadvantages of fermentation -Slow -Fermentation gives low yield (15%) as high concentration of ethanol kills the yeast -Need to carry out fractional distillation to obtain pure ethanol from the reaction mixture. Uses of alcohol: Solvent for organic compound, alcoholic drinks (ethanol), and fuel. Carboxylic acid Acid’s reactions (Neutralization) - Acid + metal  salt + H2 - Acid + base  salt+H2O - Acid + carbonate  salt + H2O + CO2 Eg: Magnesium + ethanoic acid  Magnesium ethanoate + H2 Carbonate can be used to test for carboxylic acid since effervescence is observed. Esterification Alcohol + carboxylic acid ↔ ester + H2O Eg: Ethanol + butanoic acid ↔ Ethyl butanoate + H2O C3H7COOH + C2H5OH ↔ C3H7COOC2H5 + H2O Concentrated sulfuric acid as catalyst, heat under reflux Uses of ester (has a sweet smelling): To make perfume, food flavouring, and solvent for organic chemicals Alcohol and Carboxylic acid

Macromolecules (Polymer) : Large molecules formed by joining many monomers by covalent bonds Addition polymerisation (A reaction whereby many monomers are bonded together to form a single polymer w/o any by-product) Condensation polymerisation (A reaction whereby many monomers are bonded together to form a polymer with the removal of small molecules as by-product) ~ Monomer used: Alkene ~ Name of the polymer: poly(alkene) Eg: If the monomer is ethene (gas @rtp) Then the polymer is poly(ethene) (solid @rtp) * Polymer is used to make plastic C C H H H H C H H C H H C H H C H H n Monomer : ethene A repeated unit The structure of the polymer, poly(ethene) Polyamide Polyester ~ Monomer used: Diamine and Dicarboxylic aicd ~ Monomer used: Diol and Dicarboxylic aicd Ester linkage Poly(ester) n Amide linkage Poly(amide) Eg of polyester: terylene): ~ Use : Make clothing materials Natural polymer that has the same linkage is Fats Eg of polyamide: Nylon ~ Use : To make fishing line, parachute Natural polymer that has the same linkage is Proteins Addition polymerisation 1. Double bond is broken during addition polymerisation. 2. Percentage composition/empirical formula/mass of the polymer remains the same as monomer. 3. Molecular formula, density, mp/bp of polymer is higher than the monomer. Mp/bp increases due to increase in Mr and stronger intermolecular forces of attraction between molecules. Advantages of plastic Disadvantages of plastic Light, non-fragile, cheap, durable Non-biodegradable, (Not decomposed by bacteria), take up landfill site for disposal. Give out HCl (poisonous gas) when burned. 2. 1. 1. 2.