3.1 Intro to organic Flashcards
What are the rules for nomenclature?
-to name branched alkanes you need to count how many carbons are in the longest chain and work out the stem (like you would for a straight-chained alkane)
-side chains are names according to how many carbon atoms they have and which carbon atom they are attached to
-if there is more than 1 side chain in a molecules you place them in alphabetical order
-if there are 2 or more side chains of the same type then you add a prefix of di, tri, tetra etc (ignore these when putting other prefixes in alphabetical order)
-always number the longest continuous carbon chain so that the name contains the lowest numbers possible
-if there’s more than 1 functional group you have to work out which one has the highest priority- this is the main functional group-the stem of the name then comes from the longest carbon chain containing the main functional group
order from lowest priority to highest priority:
halogens, alkyl groups, alkenes, other functional groups
What are the different types of formulae?
-empirical
-molecular
-structural
-displayed
-skeletal
Define a homologous series and give properties of them.
A family of chemicals with the same general formula but different molecular formulae.
General formula;
Chemically similar;
Same functional group;
Trend in physical properties eg inc bp as Mr increases;
Contains an additional CH2 group;
Define isomers.
-molecules with the same molecular formula
-but different structures
What is the difference between structural isomers and stereoisomers?
Structural isomers= molecules with the same molecular formula but a different structure
Stereoisomers= molecules with the same structural formula but a different spatial arrangement of atoms
What are the different types of structural isomer?
Chain - different C chains
Positional- same functional group but different positions
Functional group- different functional groups
What are the requirements of E/Z isomers?
-C=C/restricted rotation
-2 different groups on each C
CIP rules:
Priority groups have the highest atomic number
Define free radicals.
Species with an unpaired electron
(very reactive, cause cancer, destroy ozone layer)
What is the difference between electrophiles and nucleophiles?
Electrophile- a species that can accept a pair of electrons (electron deficient)
Nucleophile- a species with a lone pair of electrons to donate
Free Radical Substitution: What condition is needed for initiation?
UV light- provides energy to break Cl-Cl bond
Free Radical Substitution: What happens during termination?
Joining of any 2 free radicals
Stages of FRS
Initiation
Propagation
Termination
Explain how the CIP priority rules can be used to deduce the full IUPAC name of this compound.
Stage 1: consider the groups joined to right hand carbon of the C=C bond
Consider the atomic number of the atoms attached
C has a higher atomic number than H, so CH2OH takes priority
1
Stage 2: consider the groups joined to LH carbon of the C=C bond
Both groups contain C atoms, so consider atoms one bond further away
C, (H and H) from ethyl group has higher atomic number than H, (H and H)
from methyl group, so ethyl takes priority
Stage 3: conclusion
The highest priority groups, ethyl and CH2OH are on same side of the C=C
bond so the isomer is Z
The rest of the IUPAC name is X
Explain why the boiling points of isomers are similar.
Similar sizes
Similar intermolecular forces between molecules
Why do branched chain isomers have lower boiling points than straight chain isomers?
-less surface area
-weaker van der waal’s forces
