Module 4 - core organic chemistry Flashcards
What is the general formula for all alcohols?
Cn H2n+1 OH
Define functional group
Group of atoms in a molecule which is responsible for the reaction
What are the three main types of organic reactions
Substitution
Elimination
Addition
What are the three main organic reaction mechanisms
electrophile (likes electrons/negative charges)
nucleophile (like positive charges)
radical (unpaired electron, ver aggressive)
What are electrophiles
electron pair acceptors
what are nucleophiles
electron pair donors
define hydrolysis
breaking of covalent bonds by reaction with water
define condensation
reaction in which two molecules combine to form a larger one and in which water or anoter small molecule is formed (lost)
Define alkanes
saturated hydrocarbons
What is the formula for alkanes?
CnH2n+2
Why do branched isomers have lower boiling points than unbranched?
less surface area of contact
weaker london forces
less energy required to overcome london forces
Define homolgues series
group of compounds with the same general formula but a different fuctional group
Differ by a CH2 group
Define aliphatic
a hydrocarbon joined together in straight chains, branched chains or non aromatic rings
Define alicyclic
an aliphatic compound containing a benzene ring
Define cycloalkane
a cyclic alkane e.g. cyclohexane
Define radical
species with an unpaired electron
Define homolytic fission
each atom receives one bond electron, radicals are formed
Define heterolytic fission
one atom receives both bond electrons, ions are formed
What do full headed curly arrows show?
Movement of a pair of electrons
What do half headed arrows show?
movement of a single electron
Define alkene
Unsaturated hydrocarbons
What is the general formula for alkenes?
CnH2n
How are alkenes prepared?
from alcohols by elimination reaction or from crude oil
What do double bonds have that make them a good target for electrophillic addition?
High electron density
What do halogen atoms bind to?
carbons from the double bond
What is the test for alkenes?
shake with bromine water at room temperature
goes from orange to colourless
Describe bonding in alkanes
all four carbon bonds are sigma bonds
the orbitals overlap in just one point and can therefore rotate across axis
high bond enthalpy
tetrahedral
Describe bonding in alkenes
double bond consists of one sigma and one Pi bond
In the pi bond the P orbitals of two carbons overlap in two points (sideways) so they cannot rotate
double bonds are stronger and shorter than single bonds
high electron density
trigonal planar
Define polymer
Long chain molecules of monomers
What are the rules of polymers
draw square bracket through the middle of the bond
polymer chain is built is built only from carbons with a double bond - all other carbons form side chains
remember to put n on both sides of the equation
Define structural isomer
same molecular formula but different structural formula
What are some characteristics of alcohols
high boiling points due to hydrogen bonds
C-O bond polar
OH good leaving group
likes to undergo elimination and nucleophillic substitution reactions
acts as a nucleophile in esterifcation reactions
What is the role of ozone
absorbs high energy UV radiation which causes skin cancer
What is indicated by a higher boiling point than expected?
impurities
