10.1 organic chemsitry Flashcards
define homologous series
- series of compounds
- same family
- same general formula
- differ from each other from a common structural unit
alkane general formula
CnH2n+2
nucleophile vs electrophile
electron pair donor vs acceptor
drawing arrows convntion
full arrow — electron pair
half arrow – single electron
these are curved
chiral carbon (a sterocenter)
diff groups on all sides
how to determine if a double bond is a stereo center
if it can form cis/trans, 4 distinct grpsh
how to calculate no of enantiomers
2^no of seterocenters
nitration of benzene conditions
conc H2SO4, 50C
benzene + conc HNO3
definition nitration (of benzene)
electrophillic substitution of a H atom by a nitro grp. -MO2
equation (drawn) for nitration of benzene
(o) + HNO3 (conc) –H2SO4 (conc), 50C–> (o)–NO2 + H2SO4 (regenerated)
mechanism of nitration of benzene *
- generation of electrophile, NO2+
HNO3 + 2H2SO4 <—> NO2+ + H3O+ + 2HSO4- - no2+ attacked by delocalised pi electrons,
- 1 pair (curved arrow) removed to NO2+ –SLOW–> complicated intermediate. –> (O)–NO2 + H2SO4 (regen)
intermediate
H and NO2 on same corner, HSO4-: (curved arrow to H). (O) interior missing that end of the circle. plus sign in center
boiling point trends for organic molecules
BP incr with incr size
each -CH2- = incr London Dispersion Forces = incr
how is a molecule represented with condensed structural formula (propene?)
propene –> CH2 = CHCH3
what are strucural isomers
same molecular formula but different structural formulae
what is branch-chain isomerism
same molecular formula BUT longest hydrocarbon chain is not the same
- caused by branching
name the 3 types of structural isomerism
branch-chain
positional
functional
what are positional isomers
differences in position of functional group
what is functional group isomerism
diff functional grps result in the same molecular formula
when given a formula eg CH3CH(CH3)CH2CH3 what do the brackets mean
side chain!
how is a side chain named
it is an alkyl group!
CH3 = methyl
tri/di etc eg trimethyl – this is the total in the molecule
carbon number is listed in from eg
3, 3, 4
what if theres more than one type of side chain? how do you name them then
alphabetical order
eg 4-ethyl-2-methyl hexane
alkene general formula
CnH2n
how is the double bond in an alkene presented
but-1-ene
alkynes general formula
CnH2n-2
they have a triple bond!
pent - 1 -yne
what are arenes
compounds with 1 or 2 more rings with pi electrons that are delocalised
what compounds are aromatic
arenes
what is the one aromatic hydrocarbon covered in IB!
BENZENE !!! C6H6
what is the functional group of benzene
phenyl group
general formula of halogenoalkanes
Cn H2n+1 X
how are haloalkanes named
prefix is the halogen
chloro-
ending -ane
1,1-dibromopropane
1-bromo-2-chloropropane
what are ethers
the ones with the O in the middle
R-O-R
functional group isomers of alcohols
general formula of ethers
CnH2n+2O
naming ethers 2
meth oxy ethane
(older)
ethyl methyl ether (the two sides then ether)
what is the functional group of carbonyls
C = O
general formula for carbonyl
CnH2nO
aldehydes vs ketones
aldehydes: carbonyl grp on the end of the chain
ketones: min. 3 carbons, carbonyl not on ends
nomenclature of aldehydes vs ketones
a: – al
k: – one
ethanal
propanone
differences in reactions between aldehydes and ketones is bc of ?
the H on the aldehyde / nature of the R group
consequences of having a C=O bond (polarity)
diff in electrongeativity = polar = dipole-dipole
- higher BP (for small molc)
- solubility in water for lower members
carboxylic acids general formula
RCOOH
what are esters
functional grp isomers of carboxylic acids
carboxylate
-COOR
nomencalture of esters
so its like the C=O sticks out and the -C-O- is bonded to groups SO the name “methyl ethanoate” the first part is for the group bonded to the O, the second is for the part bonded to the C (including the C)
so that would be
C - C - O - C
O
why are chemical and physical properties of carboxylic acids and esters different despite benig functional group isomers
carboxylic acids have H-BONDS
CA: smaller chain soluble in water, higher BP
esters: insoluble, lower BP
amines vs amides vs nitriles
amines: NH2
amides: CONH2
nitriles: CN (cyanide grp)(triple bond)
what is sterochemistry
the study of relative spatial arrangements of atoms in molecules
how to determine if its a primary, secondary, or tertiary alcohol/halogenoalkane
ok so look at the carbon that the OH is attached to. then how many C atoms is that C attached to. tahts it
primary sec ter for AMINES yes its different
number of alkyl grps attached to the N
kekules structure for benzene PROBLEMS 3
- similar reactivity to ethene: NAH ethene has addition reactions while benzene has substitution reactions
- shorter double, longer single bonds: ERM ACTUALLY they were the same lenght
- banzene is actually more stable than expected
lenght of bonds in benzene
intermediate between single and double bonds
kekule strucure for benzene
hexagon with 3 double bonds
equivalent to 3 ethene molecules
why is benzene more stable than expected
delocalisation energy from the delocalised electrons
benzene is a (shape) with bond angles of ()
planar regular hexagon
120 degrees
all carbons in benzene are sp?
sp2
forms sigma bonds with
explain the delocalisation of electrons in benzene
sp2 hybridised carbons form sigma bonds with 2 other C + 1 H
remaining p orbital overlaps = forms system of pi bonds spread across whole ring
electrons are not bound to specific atoms, freely move around
