Core Organic Chemistry Flashcards
What’s a homologous series?
A series of compounds with similar chemical properties whose successive members differs by the addition of a -CH2- group.
What’s a functional group?
The part of molecule responsible for the chemical properties.
Aliphatic
carbon atoms arranged in line (branched or unbranched)
Alicyclic
carbon atoms arranged in a ring (branched or unbranched)
Aromatic
carbon atoms mostly arranged in a benzene ring
Suffix for aldehyde & ketone
Aldehyde: -al
Ketone: -one
Structural isomerism
Same molecular formula but different structural formula
Homolytic fission
Each atom has a single electron
Radicals are formed
Heterolytic fission
One atom takes both electrons
Negative & positive ions are formed
Addition reaction
2 reactants form 1 product
Substitution reaction
An atom/group is displaced by a more reactive atom/group.
Elimination reaction
Removal of small molecule from bigger one. 1 reactant makes 2 products
General formula for alkanes
CnH2n+2
General formula for alkenes
CnH2n
General formula for alkynes
CnH2n-2
General formula for alcohols
CnH2n+1OH
General formula for haloalkanes
CnH2n+1X (X is a halogen)
General formula for carboxylic acids
CnH2n+1COOH
General formula for aldehydes
CnH2nO
General formula for ketones
CnH2nO
Bond angles and arrangement for alkanes
109.5º
Tetrahedral
Why does boiling point of alkanes increase as chain length increases?
- Larger surface area
- More contact
- More London forces
- Stronger bonds
Why do branched alkanes have lower boiling point?
- Branches allow for less contact area
- Less London forces
- Weaker bonds
Combustion of alkanes
Alkane + Oxygen –> Carbon dioxide + water
Incomplete combustion of alkanes
Form water and carbon monoxide/carbon
Reaction of alkanes with halogens
Alkane + Halogen –> Haloalkane + hydrogen halide
- Needs sunlight (UV)
Stages of radical substitution
1) Initiation
2) Propagation
3) Termination
Initiation (Radical substitution)
- Halogen covalent bond broken by homolytic fission
- Forms radicals
- Needs sunlight (UV)
Propagation (Radical substitution)
1) - Br radical reacts with C-H bond
- Forms CH3 radical and HBr
2) - CH3 radical reacts with Br, forming CH3Br, and Br radical
Termination (Radical substitution)
2 radicals collide forming a molecule with all electrons paired
Shape & angle around a double bond
Trigonal planar (120º)
Stereoisomers
Same structural formula but different arrangements of atoms
E/Z isomerism
E Isomerism: Different sides
Z Isomerism: Same sides
Cis-Trans isomerism
Same as E/Z isomerism, but hydrogen is attached to carbon
Hydrogenation of alkenes
Alkene + hydrogen –> Alkane
Ni Catalyst
Halogenation of alkanes
Alkene + halogen –> Haloalkane
Testing for unsaturation (double bond)
Add bromine water to substance,
if it turns colorless, it has a double bond
Alkenes + hydrogen halides
Alkenes + hydrogen halides –> Haloalkane
Hydration of alkenes
Alkene + steam –> alcohol
Electrophiles
- Positive charge
- Attracted to electron-rich region
- Accepts electrons
Nucleophile
- Negative charge
- Attracted to electron-deficient region
- Donates electrons
Electrophilic addition mechanism
1) Bond donates 2 electrons to Hydrogen in HBr, H-Br bond electrons go to Br
2) Carbocation is formed, Br reacts with it
3) haloalkane is formed
Markownikoff’s rule
Major product: Secondary carbocation
Minor product: Primary carbocation
Carbocation stability
Stability increases In increasing carbocation classification
Primary < Secondary < Tertiary
Polyethene
Plastic bags, bottles, toys
Poly(chloroethane)
Pipes, bottles, sheets…
Can be rigid or flexible
Disposing methods of polymers
- PVC Recycling
- Using polymers as fuels
- Feedstock recycling (obtain raw materials)
Bioplastics
- Photodegradable
- Biodegradable
Alcohols vs Alkanes
- Higher melting points
- Less volatile
- Greater solubility
Why do alcohols have stronger bonds
- Polar bonds
- Hydrogen bonds
Primary alcohol
carbon attached to 1 alkyl group
Secondary alcohol
carbon attached to 2 alkyl groups
Tertiary alcohol
carbon attached to 3 alkyl groups
Combustion of alcohols
Alcohol + Oxygen –> Carbon dioxide + water
Oxidation of primary alcohols
- Can form aldehyde (distillation)
- Can form carboxylic acids (reflux)
Oxidation of secondary alcohols
Oxidized to ketones
Dehydration of alcohols
Alcohol –> Alkene + water
- acid catalyst
- reflux
Substitution reaction of alcohols
Alcohol + hydrogen halide –> haloalkane + water
- Could also add NaX with (H₂SO₄)
Nucleophilic substitution
halogen is substitution by nucleophile in haloalkane
Hydrolysis of haloalkanes
Haloalkanes –> Alcohols
Which OH is removed in ester bond
-OH from carboxylic acid
