Organic chemistry and alkanes Flashcards
Saturated definition
Contains C-C single bonds
Unsaturated definition
Contains C-C multiple bonds
Aliphatic definition
Chain of carbon atoms
Aromatic definition
Contains benzene ring (unsaturated)
Alicyclic definition
Chain of carbon atoms joined together in a ring
Hydrocarbon definition
A compound containing carbon and hydrogen ONLY
Homologous series definition
Contain the same functional group but each successive member of a homologous series differs by CH2
Functional group definition
The part of the organic molecule responsible for its chemical reactions
What is rule 1 for naming alkanes?
Count the largest carbon chain, the number gives the stem of the name
What are the stem names?
1: meth
2: eth
3: prop
4: but
5: pent
6: hex
7: hept
8: oct
What is rule 2 of naming alkanes?
Number the carbons to ensure that the functional group (branch) is attached to the lowest number possible
What are the branch names?
CH3: methyl
C2H5: ethyl
C3H7: propyl
What is rule 3 of naming alkanes?
If there is more than one of the same group, number the chain to give them the lowest number possible (use di/tri/tetra prefixes)
What is rule 4 of naming alkanes?
Prefixes are arranged alphabetically
What are the haloalkane names?
F: fluoro
Cl: chloro
Br: bromo
I: iodo
What are the 4 rules for naming alkenes?
- Name ends with ‘ene’
- Double bond given lowest number possible
- Double bond takes priority over other groups (apart from OH)
- Apart from in propene, the position of the double bond must be shown
What are the 2 rules of naming alcohols?
- Name ends with ‘anol’
2. OH group given the lowest number possible and takes priority over other groups
Structural isomer definition
Molecules with the same molecular formula but with a different structural formula
How does boiling point decrease for alkanes with the same molecular formula?
More branching = reduced points of contact between molecules which leads to weaker London forces between molecules so they require less energy to break –> boiling point decreases
What does incomplete combustion produce?
CO + H2O
Why does incomplete combustion occur?
Insufficient oxygen
Sigma bond definition
Head-on overlap of two atomic orbitals directly in a line between two bonded atoms
Mechanism definition
A sequence of steps showing the path taken by electrons
What is the mechanism of the halogenation of alkanes?
Radical substitution
What is the conversion of the halogenation of alkanes?
Alkane + halogen –> haloalkane + hydrogen halide
What conditions are required for the halogenation of alkanes?
UV light
What is the first step of radical substitution?
Initiation (making radicals)
Radical definition
A species with an unpaired electron
Homolytic fission definition
The breaking of a covalent bond where one of the bonded electrons goes to each atom and 2 radicals form
What is the second step of radical substitution?
Propagation (radicals taking an atom)
What do propagation steps involve?
A radical reacting with a non-radical
What is the equation for the first step of the propagation of Cl.?
Cl. + CH4 –> CH3. + HCl
What is the equation for the second step of the propagation of Cl.?
CH3. + Cl2 –> CH3Cl + Cl.
What does Cl. act as in propagation?
A catalyst
What is the third step of radical substitution?
Termination (radical + radical –> non-radical)
What is further substitution?
Where hydrogen atoms keep being substituted for Cl.
How are isomeric products formed from chain reactions?
For alkanes more than 2 carbons in length any of the hydrogen atoms may be substituted, leading to a mixture of different isomers
