organic chemistry
- Created by: LauraNannini
- Created on: 21-04-20 05:44
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- Topic 6 a
- Electrophile
- Positive charge and are attracted to electrons
- Not all have positive charge- some can accept a lone pair of electrons
- Nucleophiles
- Have a lone pair or a negative charge
- Attracted to the nucleus
- Types of reactions
- Polymirisation- monomers join together to make longer chains
- Elimination-atoms a break away from a larger molecule
- Hydrolisis- splitting a molecule in two using OH- or H+ from a H2O molecule
- Addition- joining of molecules to make longer ones
- Substitution- replacing one atom with another molecule
- Reduction- when a species gains electrons
- Oxidation- When a species loses electrons
- Alkanes
- Properties
- CnH2n+2
- Saturated hydrocarbons
- Used as fuels from crude oils
- Relatively unreactive
- Non polar solvent
- Fractional distilation
- Crude oil is heated and the smaller hydrocarbons go to the top colomns and the larger ones to the bottom
- Cracking and reforming
- To break long chains into smaller chains that are in higher demand
- High temperatures required and usually introduc a catalyst to lower the activation energy
- Reforming is straight chain alkanes that change to branched and cyclic alkanes
- Fuels
- NO2- acid rain
- CO- poison to people
- Catalytic converters prevent harmful gases from going into the atmosphere
- Fermentaion of ethanol from sugar canes is an alternative fuel
- Homolytic fission
- splits a bond by providing both electrons to one atom forming
- Heterolytic fission
- splits a bond by providing both electrons to one atom forming a + & - ion
- Free radical substitution
- Alkane + Halogen --> Halogenoalkane + HCL
- Presence of UV light
- Type of homlytic fission
- Properties
- Alkenes
- Properties
- CnH2n
- Unsaturated hydrocarbons (C=C)
- Reactive due to their double bond
- non-polar and doesn't dissolve in water
- Electrophilic addition
- Alkenes + hydrogen
- Double bond breaks and the two hydrogens join the carbons
- Nickel catalyst is used
- Alkenes + hydrogen halides
- Room temperature needed
- Double bond breaks and the H acts as an electrophile. Br is more electronegative so H goes to where it is electron rich
- Alkenes + halogens
- Room temperature needed
- Color goes from brown-red to colourless
- Bromine acts as electrophile
- Alkenes + bromine water
- Color goes from brown-red to colourless
- Alkenes + water
- Makes an alcohol
- 300 degrees at 60-70 atm needed
- H3PO4 is used as a catalyst
- Alkenes + hydrogen
- Oxidation
- Alkenes + potassium manganate
- Room temperature needed
- Purple to colourless
- {O} used as oxidising agent
- A 'Diol' is made
- Alkenes + potassium manganate
- Poly-alkenes are repeating units of the same monomer
- Properties
- Disposal of waste polymeres
- Incineration- burnt and release greenhouse gases
- Recycling- Saves crude oil supplies
- Some can be cracked into further smaller alkenes
- Biodegradable- can be broken down by UV light or rain
- Electrophile
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