B3 Organic Chemistry I Flashcards
How are two numbers seperated in organic nomenclature
Comma
How are numbers and letters seperated in organic nomenclature
Dash
Which carbon number does the highest priority functional group get
The lowest carbon number
Where there are the same priority groups, which group gets the lowest carbon number
First group alphabetically
General formula of alkyl groups
Six carbon prefix
Hex
Seven carbon prefix
Hept
Nine carbon prefix
Non
Ten carbon prefix
Dec
Define empirical formula
The simplest whole number ratio of atoms of each element present in a compound
Define molecular formula
The total number of atoms of each element present in a molecule
Define homologous series
- A series of organic compounds with the same functional group
- But with each successive member differing by CH2
What is an aliphatic compound
- Contains hydrogen and carbon atoms
- Joined in a straight chain, branched chain, or non-aromatic ring
What is an alicyclic compound
- An aliphatic compound
- Arragned in non-aromatic rings
- With or without side chains, but no benzene ring
What is an aromatic compound
Contains a benzene ring
How are benzene rings drawn
Relationship between compounds being alicyclic and aliphatic
- All alicyclic are aliphatic
- Not all aliphatic are alicyclic
What is a saturated compound
Contain single carbon-carbon bonds only
What is an unsaturated compound
Contain multiple carbon-carbon bonds
Define structural isomers
Compounds with the same molecular formula, but different structural formulae
Define homolytic fission
Each bonding atom recieves one electron from the bonded pair, forming two radicals
Define heterolytic fission
One bonding atom recieves both electrons from the bonded pair, forming an ion
Define radical
A species with an unpaired electron
Define Curly Arrow
The movement of a pair of electrons, showing either heterolytic fission, or the formation of a covalent bond
What is the only type of covalent bond present in alkanes
Sigma bonds
Why do alkanes have a low reactivity
- High bond enthalpy of the C-H and C-C bonds
- Low bond polatiry of the C-H and C-C bonds
General formula of alkanes
General formula of cyclic alkanes
What bonds will be present in a single covalent bond
A sigma bond
What bonds will be present in a double covalent bond
One sigma bond, one pi bond
Ways to comapre sigma and pi bonds
- Orbital overlap
- Bond enthalpy
- Electron density
- Rotation
What bonds will be present in a triple covalent bond
One sigma bond, two pi bonds
Sigma vs Pi: Orbital overlap
- Orbitals overlap directly between bonding atoms in sigma
- Sideways overlap of adjacent p-orbitals above and below the bonding atoms in pi
Sigma vs Pi: Electron density
Sigma have a much higher electron density than pi bonds
Sigma vs Pi: Rotation
- Sigma have free rotation
- Pi have restricted roation
Sigma vs Pi: Bond enthalpy
- Sigma have a higher bond enthlapy so are stronger
- Pi have a lower bond enthalpy so are weaker
- More energy is requred to break sigma bond than pi bond
Explain why a longer carbon chain alkane has a higher boiling boint than a shorter carbon chain alkane
- Longer carbon chain means larger surface area for contact of London forces acting between molecules
- London forces therefore stronger
- More energy required to break London forces
Explain why the more branched an alkane’s carbon chain is, the lower it’s boiling point
- More branched carbon chain means smaller surface area for contact of London forces acting between molecules
- Weaker London forces
- Less energy requreid to break London forces
Word equation for alkane complete combustion
Word equation for alkane incomplete combustion
Produces Carbon Monoxide which is toxic
Why is alkane incomplete combustion hazardous
Produces carbon monoxide which is toxic
What condition is required for Free Radical Substitution and why
- UV Light
- Provides energy to break covalent bond (homolytic fission)
Free Radical Substitution: initation step for chlorine and butane
Free Radical Substitution: propagation steps for chlorine and butane
Free Radical Substitution: Termination steps for chlorine and butane
Why is Free Radical Substitution limiting to produce a desired product
- Substitution can replace any hydrogen atom in any position along carbon chain
- Further substitution can occur
- There is more than one termination step, so more than one termination products
General formula for alkenes
Functional group of alkenes
C=C bond
Why are alkenes very reactive
The pi bond in the C=C bond has a low bond enthalpy
Draw a labelled diagram of a pi bond
Define stereoisomers
Compounds with the same structural formula, but with a different arrangement in space
When can E/Z isomerism occur in alkenes
When each carbon involved in the C=C bond, has two different groups bonded to it
When would an alkene not have steroisomers
If one/both the carbons involved in the C=C bond has two of the same groups attached
In stereoisomerism, how do you decide on priority groups
Group with highest atomic number