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Organic Chemistry - Coggle Diagram
Organic Chemistry
Alcohols
Description
- Hydroxyl functional group (-OH)
- CHO
- CnH2n+1OH (where n=1,2,3 etc)
- -ol
- Each member differs by -CH2- unit
Isomerism
- Same molecular formula, different structural formula
- Different physical properties
Physical Properties
- Alcohols with lower relative molecular masses
- Generally volatile
- Generally soluble (decrease with increase in molecular size)
Reactions
- Excess oxygen: water vapour and carbon dioxide
- Burns with a "cleaner flame" (less sooty) compared to alkane -> lower percentage of carbon
- Highly exothermic - used as fuels
FORM CARBOXYLIC ACID
- Atmospheric oxygen
- Heating with acidified aqueous potassium manganate (VII) or acidified aqueous potassium dichromate (VI)
- Colourless to purple
- Orange to green
- Ethanol molecule
- Loses 2 hydrogen atoms
- Gains 1 oxygen atom
- Products: Water
FORMS ALKENES
- Decomposition reaction involving removal of elements of water from compound using dehydrating agent (removes hydrogen & oxygen from other compound)
Conditions: Concentrated sulfuric acid (dehydrating agent), 170 Degree Celsius
Application: Breathalyser works on principle of oxidation of alcohol
- B with Acidified potassium dichromate (VI) used by traffic police to test amount of alcohol consumption
Manufacture
- Catalytic Addition of steam to ethene (hydration of alkene)
Conditions: 300 Degree Celsius, 65atm, Phosphoric (V) Acid as catalyst
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Conditions: Yeast, Best at 37 Degree Celsius, In the absence of air (O2)
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Uses
- Alcoholic Beverages
- Solvent for paint
- Fuel for vehicles
Carboxylic Acids
Description
- Carboxyl Functional Group (-COOH)
- CnH2n+1COOH (where n=0,1,2 etc)
- -oic acid
- Each member differs by -CH2- unit
Manufacture
- Oxidation of ethanol by heating with oxidising agent e.g. acidified aqueous potassium manganate (VII)
- Oxidation of ethanol by atmosphetic oxygen
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Uses
Food as flavouring, preservative
Physical Properties
- MP and BP increase down homologous series
- Solubility in water decreases down homologous series
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Alkanes
Physical Properties
- Insoluble in water
- Soluble in organic solvents
- Melting and Boiling Points
- Larger the relative atomic mass, higher the MPBP
- More energy required to overcome stronger intermolecular forces of attraction between larger alkane molecules
- Viscosity - Larger relative molecular mass, more viscous alkane (flow less easily) - Due to stronger intermolecular forces of attraction between larger molecules
- Flammability
- Larger relative molecular mass, less flammable alkane
- As percentage of carbon present increases, more difficult to burn alkane (flame produced more sooty and smoky)
Isomerism
- Same molecular formula, different structural formula
- Different physical properties
- Straight chain alkanes higher B.P. than branched chain alkanes
Applications:
- Car engines run better on burning branched-chain alkanes compared to straight chain alkanes
- Petrol fraction from fractional distillation contain a lot of straight chain alkanes
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Description
- Saturated Hydrocarbons
- C-C (single covalent bonds)
- -ane
- Each member differs by CH2 unit
Reactions
- Alkanes burn readily in air when ignited by spark of flame
- Highly exothermic, make good fuels
- Complete combustion (Sufficient/excess oxygen): water and carbon dioxide
- Incomplete combustion (Insufficient oxygen): water, carbon (soot) and carbon monoxide
Conditions:
- Ignition by spark or flame
- Oxygen
- Direct replacement of an atom in a molecule with another atom
- React with halogens
- Slow reaction
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Alkenes
Description
- Unsaturated Hydrocarbons
- C=C
- -ene
- Each member differs by CH2 unit
Isomerism
- Re-arranging carbon chain
- Shifting position of C=C
*Isomers may not come from the same homologous series
Physical Properties
- Insoluble in water
- Soluble in organic solvents
- Melting and Boiling Points
- Larger the relative atomic mass, higher the MPBP
- More energy required to overcome stronger intermolecular forces of attraction between larger alkane molecules
- Viscosity - Larger relative molecular mass, more viscous alkane (flow less easily) - Due to stronger intermolecular forces of attraction between larger molecules
Reactions
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Addition of Bromine
- Orange aqueous bromine decolourise rapidly
- Used to test for presence of unsaturated hydrocarbons
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- Excess oxygen: water vapour and carbon dioxide
- Contain relatively higher percentage of carbon than alkanes with same number of carbon atoms -> burn with more sooty flame
Catalytic Cracking
Description
1. Definition: Break down long-chain hydrocarbons into shorter chain hydrocarbons by passing hot vapourised hydrocarbons over heated catalyst
- Rate of cracking and end products: dependent on the temperature and presence of catalyst used
Conditions
- Aluminium oxide and silicon dioxide as catalyst
- 600 degree celsius
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Importance
- Converts heavy petroleum fractions
-Lubricating oil or diesel oil: High in supply but low in demand INTO
- Lighter fractions like petrol: Low in supply, high in demand
- Produce large amount of shorter chain alkenes
- Useful to make plastics, ethanol and other useful chemicals
- Produce hydrogen: used in manufacture of
- Ammonia (Haber Process)
- Hydrogen Fuel cells
Macromolecules
Description
- Very large molecule, made up of many atoms covalently joined together
- Polymer: type of long chain molecule formed when many small molecules (monomers) linked together
- Polymerisation: process of joining together a large number of monomers to form a polymer
Addition Polymerisation
- Monomer units join together without losing any atoms
- Each monomer forms single bonds with 2 other monomers, join to form polymer
Conditions: High pressure, temperature and catalyst
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Esters
- Functional group (-COO)
- Colourless liquid, insoluble in water
- Sweet smell, found in fruits and responsible for fruity smell
Uses
- Artificial food flavourings
- Small molecular size - volatile liquids, solvents for cosmetics, perfumes and glues