m4 - organic Flashcards
functional group def
a group of atoms responsible for the characteristic reactions of a compound
functional group carboxylic acid suffix
-oic acid
functional group ketone suffix and prefix
-one
-oxo
functional group aldehyde suffix and prefix
-al
-oxo
functional group alcohol suffix and prefix
-ol
-hydroxy
functional group ester suffix
alkyl -anoate
eg ethyl ethanoate
skeletal formula rules
no carbons, no hydrogens
- there are Os and OHs though
homologous series def
a series of organic compounds having the same functional group but with each successive member differing by CH2
- there is a trend in physical properties (gradual change)
structural isomer def
compounds with the same molecular formula but different structural formulae
stereoisomerism def
compounds with the same structural formula but with a different arrangement in space
cis-trans isomers
two of the groups attached to each carbon of the C=C are the same
eg HO-C=C-OH
see booklet for diagrams of cis-trans
cis: 2 groups are near each other / facing each other
trans: 2 groups are on opposite side
E/Z isomerism
e = entgegen (opposite)
z = zusammen (together)
most important group that comes off C=C double bond = highest atomic number
are they on same side or opposite
due to restricted rotation of a double bond
bond names in alkanes and why
σ-bonds -> formed by (overlap of orbitals directly between the bonding atoms)
atomic orbitals combine to form molecular orbitals
alkane reactivity
bonds between C and H are strong, so not very reactive
- alkanes do take part in some chemical reactions
boiling point in straight chain alkanes
increases because as chain length increases, number of e- in the molecule increases
london forces increase
more energy required to overcome intermolecular forces
isomeric alkanes
branched chains have lower boiling points than straight chains
branched chains have a smaller surface area for london forces to act through (can’t get as close to each other)
so smaller attraction between molecules
H-C-C-C-C-C-H can get closer to each other than branched
reactions of alkanes
they readily combust with oxygen to produce CO2 and H2O
- if insufficient oxygen, incomplete combustion occurs to produce CO or C, with H2O
(carbon monoxide is poisonous, takes the place of oxygen in haemoglobin (coordinates to an Fe2+ ion which is part of the haem found in rbc’s)
mechanisms, curly arrow
shows movement of a pair of e-
starts from a bond (X-Y) or a lone pair HO:) or a -ve charge (HO-)
only ever from a -ve to a +ve, not other way round
organic reaction mechanisms: homolytic fission
radicals generated (a species with an unpaired e-)
X-Y -> X. + Y.
can be shown by half curly arrows from bond to each atom
alkanes reaction with halogens (CH4 +Cl2)
initiation, propagation, termination
initiation: - first step in a radical substitution reaction
- halogen-halogen bond is broken to form free radicals (with UV light)
Cl2 —UV—> 2Cl.
propagation: (two repeated steps in radical substitution that build up the products in a chain reaction)
- Cl. + CH4 -> HCl + CH3. (Cl causes a CH bond to break and leaves with the H)
- CH3. + Cl2 -> CH3Cl + Cl. (radical Cl. then repeats process)
termination: (two radicals combine to form a molecule)
- Cl. + Cl. -> Cl2
- CH3. + CH3. -> C2H6 ethane
- Cl. + CH3. -> CH3Cl