organic Flashcards
(111 cards)
1
Q
Catalytic converters
A
remove unburnt hydrocarbons, oxides of nitrogen and carbon monoxide from exhausts
2
Q
Flue gas desulphurisation
A
removes SO2 using CaO or CaCO3
3
Q
Free radical substitutions require what and have which 3 steps
A
UV light
Initiation, propagation, termination
4
Q
Thermal cracking
A
produces a high percentage of alkenes and uses high pressures and high temperatures
5
Q
Catalytic cracking
A
uses a zeolite catalyst, slight pressure and high temperature. Catalytic cracking produces aromatic hydrocarbons and motor fuels
6
Q
Alternatives to CFCs
A
include HFCs and hydrocarbons
7
Q
Depletion of ozone
A
Cl + O3 ClO* + O2
ClO + O3 2O2 + Cl*
*Overall: 2O3 3O2
*UV light breaks C-Cl bonds in CFCs
8
Q
- Ozone formed
A
O2 O + O*
O2 + O O3
*O3 prevents a lot of UV radiation from the sun from reaching earth
*UV radiation causes sunburn and skin cancer
9
Q
Elimination – hydroxide ions must be dissolved in ethanol
A
- Anhydrous conditions
- Hydroxide ions act as a base
- Accept a proton from the carbon atom
10
Q
mechanism forming alkene from haloalkane
A
elimination reaction
11
Q
what conditions for elimination
A
reflux
12
Q
Reagent for nucleophile substitution reactions
A
Ethanolic potassium cyanide
13
Q
Formation of alcohols through nucleophilic substitution reactions
A
warm aqueous potassium or sodium hydroxide
14
Q
formation of amines needs
A
- Hydrolysis
- Reagent = excess ethanolic ammonia
- The amine group has a lone pair of electrons, acts as a nucleophile
15
Q
uses of PVC
A
properties can be modified with a plasticiser
rigid PVC used for drain pipes, window frames
16
Q
what is plasticised pvc used for
A
cable insulation, clothing and tiles
17
Q
why are polymers unreactive
A
main carbon chain is non-polar and saturated
18
Q
addition reactions with Br2
A
produces a dihalogenoalkane
Br2 molecule is polarised by double bond
double bond repels electrons in Br-Br bond
19
Q
addition reactions with HBr
A
produces halogenoalkane
if the alkene is asymmetrical there are 2 possible products
cold concentrated sulfuric acid catalyst
produces alcohol
20
Q
addition reactions with H2SO4
A
major produce is produces via the most stable carbocation intermediate
minor product is produced from the other carbocation intermediate
if asymmetrical there are 2 possible products
cold conc, sulfuric acid acts as a catalyst
produces an alcohol
21
Q
bromine water used to test for unsaturation in hydrocarbons
A
orange bromine water decolourises when mixed with an alkene
22
Q
fermentation of glucose producing ethanol temperature
A
30 - 40 celsius
23
Q
what is yeast used for in fermentation of glucose to produce ethanol
A
enzyme
24
Q
equation for fermentation of glucose produces ethanol
A
C6H12O6 –> 2C2H5OH + 2CO2
25
biofuel
ethanol made via fermentation
biofuels are carbon neutral
26
decision surrounding use of biofuels
land used for biofuels cant be used for crops
all car engines would need modifying to use different fuels
27
are biofuels carbon neutral
fossil fuels must be burnt to power machinery and provide transportation
28
how do you separate ethanol when fermenting glucose
fractional distillation
29
hydration of alkenes
produces alcohols
30
what is needed to produce alcohols from alkenes
acid catalyst = phosphoric acid catalyst
and steam
31
what is needed to produce alkenes from alcohols through elimination reactions
- concentrated sulfuric acid catalyst
- product requires distillation
- alkenes produced from a renewable resource --- addition polymers can be produced without the need for crude oil
32
oxidation of alcohols agent
acidified potassium dichromate
33
what are primary alcohols oxidised to
aldehydes
- distillation apparatus required to obtain the aldehyde
- aldehydes oxidised to carboxylic acid
- reflux apparatus to obtain the carboxylic acid
34
what are secondary alcohols oxidised to
ketones
35
are tertiary alcohols easily oxidised
no
36
test for alkenes
orange bromine water decolourises in the presence of an alkene
37
test for aldehydes
tollens - silver mirror
fehlings - blue to red
38
test for alcohols
- add acidified dichromate
- tertiary alcohols wont react
- primary and secondary will react and solution will turn from orange to green. test new solution for an aldehyde to determine if primary or secondary. aldehyde present = primary
39
test for carboxylic acids
- add sodium carbonate
- if present, then solution will fizz due to CO2
- CO2 will turn limewater cloudy
40
high resolution mass spectrometry
- measures molecular and atomic masses
- allows you to distinguish between compounds which have the same Mr
41
infrared spectroscopy works how
different covalent bonds absorb infrared radiation at distinctive wave numbers
42
fingerprint region
500 - 1500
unique to each compound
43
infrared radiation absorption contributes to global warming
greenhouse gases absorb infrared radiation
radiation re-emitted back toward the earth
increase in concentration of greenhouse gases increases the temperature of the earth
44
what is a racemic mixture
contains exactly equal quantities of each enantiomer from an optically active compound
45
do racemic mixtures display optical activity and why
because the enantiomer cancel out each other's rotation of light
46
how is racemic mixture formed
produced from reactions which involve planar bond
planar bond has equal chance of being attacked from above or below
47
what are optical isomers
mirror images, cannot be superimposed
48
what do optical isomers have
chiral carbon
49
what are enantiomers
optical isomers
same structural formular but different arrangement in space
50
rotate plane-polarised light
one enantiomer will rotate light in a clockwise direction, and one in an anticlockwise direction
51
do ketones easily undergo oxidation
no
52
nucleophilic addition with aldehydes and ketones
react with potassium cyanide
produces hydroxynitriles - produces a mixture of enantiomers if the aldehyde/ketone is asymmetrical
53
potassium cyanide
irritant
reacts with water to produce hydrogen cyanide
hydrogen cyanide is extremely toxic
54
aldehydes can be reduced to what
primary alcohols
55
ketones can be reduces to what
secondary alcohols
56
what is the reducing agent for aldehydes and ketones
NaBH4
57
what is the mechanism in reduction of aldehydes and ketones
nucleophilic addition
58
benzene bonding
- one pair of unpaired electrons per carbon
- forms a ring of delocalised electrons
- delocalised ring of electrons means benzene is very stable
- benzene more stable
- all C-C bonds same length
- length between C-C bonds in benzene is between the length of C-C and C=C bonds
59
what mechanism is in nitration
electrophilic substitution
aromatic compounds attract nucleophiles due to dense benzene ring
destroy stable benzene ring
60
what temperatures do mononitration occur
<55 celsius
61
what does nitration of aromatics produce
nitrobenzene
62
reagents for nitration of aromatics
concentrated nitric acid and sulfuric acid
produce the NO2+ electrophile
sulfuric acid acts as a catalyst
63
friedel crafts acylation
aromatics heated under reflux in a non-aqueous solvent
produces phenylketones
64
mechanism of friedel crafts acylation
electrophilic substitution
65
what catalyst for friedel crafts acylation
AlCl3
generates electrophile from the acyl chloride
66
which is used more in industry: ethanoic anhydride or enthanoyl chloride
ethanoic anhydride because it is cheaper and safer
67
nucleophilic addition-elimination
acid anhydride and water
produces carboxylic acid
68
nucleophilic addition-elimination
acid anhydride and amines
produces N-substituted amide
69
nucleophilic addition-elimination
acid anhydride and alcohol
produces an ester
70
nucleophilic addition-elimination
acid anhydride and ammonia
produces an amide
amide have functional group -CONH2
71
acyl chloride functional group
-COCl
72
carboxylic acids
weak acids
73
carboxylic acids react with alcohols
condensation reaction
esterification reaction
forms esters
strong acid catalyst required e.g. conc sulfuric acid
74
carboxylic acid react with carbonates
form co2
75
animal fats and vegetable oils are esters of what
propan-1,2,3-triol (glycerol)
76
fats and oils can produces soap and glycerol how
alkaline hydrolysis
77
naming esters
first part from alcohol, second from carboxylic acid
78
common uses of esters
flavourings
plasticisers
perfumes
solvents
79
functional group of esters
-COO-
80
what is biodiesel a mixture of
methyl esters of long chain carboxylic acids
81
how is biodiesel produced
reacting vegetable oils with methanol with a potassium hydroxide catalyst
82
formation of aromatic amines
- reduction of nitro aromatic compound
- react with tin metal and conc HCl followed by alkali
- obtains aromatic amine from salts
83
heating a halogenoalkane with ammonia
- formation of aliphatic amines
- nucleophilic substitution reaction
- produces mix of primary, secondary and tertiary amines and quaternary ammonium salts
- excess ammonia favours primary amine
84
reduction of a nitrile
- forms aliphatic amine
- react with LiAlH4 in a non-aq solvent followed by dilute acid
OR
- react with hydrogen and a nickel catalyst
85
industrially: form aliphatic amine with hydrogen and nickel or with LiAlH4
hydrogen and nickel catalyst
more affordable
86
quaternary ammonium salts
- formed when nitrogen atom forms four covalent bonds
- forms positive ion
- used as cationic surfactants
- used in fabric cleaners and hair products
87
nucleophilic properties of amines
- lone pair of electrons on nitrogen atom
- nucleophilic sub with halogenoalkanes
- nucleophilic addition-elimination reactions of primary amines and ammonia with acyl chlorides and acid anhydrides
88
amines can form dative covalent bond
lone pair of electrons on nitrogen
dative covalent bond with H+ ion
89
base strength of amine depends on
availability of lone pair of electrons
- ammonia is a stronger base than aromatic amines
- on aromatic amines the N lone pair is delocalised so less available to accept proton
- primary aliphatic ammines are stronger bases than ammonia due to positive inductive effect pushing e- onto N, makes lone pair more available to accept proton
90
which are more rigid : condensation or addition polymers
condensation
permanent dipole dipole and hydrogen bonds
polar bonds
91
polymers in landfill
- cheap and easy
- methane released in decomposition
- large areas of land
- leaks contaminate water supplies
92
recycling polymers
- contamination of plastic can occur during recycling
- involved collecting, sorting, processing
- involves raw materials
- cheaper than making new plastics
93
incineration of polymers
toxic gases released - scrubbers must be used to remove HCl
heat produced can be used to generate electricity
94
are polymers biodegradable
condensation are
- broken by hydrolysis
- slow
addition polymers are chemically inert
- difficult to dispose of
- non-polar chains
95
cisplatin adverse effects
prevents healthy cells from reproducing therefore hair loss and suppresses immune system
96
cisplatin as anticancer drug
- binds to DNA and causes kinks in helix
- stops tumour cells replicating
- ligand replacement reaction
- a bond is formed between platinum and a nitrogen atom in guanine
97
13C NMR standard
tetramethylsilane (TMS)
98
what is NMR
different amounts of energy absorbed by nuclei in dif environments
used to determine structure of molecules
99
samples in H NMR dissolved in what
deuterated solvents or CCl4
100
what is used as standard in NMR and why
TMS (tetramethylsilane)
- produces a single peak away from other peaks
- inert and non toxic
- volatile and easy to remove
101
separation in chromatography depends on
distribution of substances in mobile and stationary phase
102
gas chromatography
- used to separate volatile liquids
103
stationary phase of gas chromatography
solid or solid coated in liquid
solid packed into a long coiled tube ration
104
mobile phase of gas chromatography
unreactive carrier gas
105
what is gas chromatography usually followed by
mass spectrometry
106
thin layer chromatography mobile phase
solvent
107
thin layer chromatography stationary phase
glass or metal plate coated in silica or alumina
108
column chromatography used for
separating solutions
more soluble chemical has a higher affinity for the solvent
therefore travels quicker through column
109
mobile phase of column chromatography
mixture allowed to drain down column along with mobile phase
110
stationary phase of column chromatography
stationary phase in a glass column packed with slurry of an absorbent material
111
TLC solvent moves up paper carrying substances in mixture
- more soluble chemical spends more time in solvent
- means it will move further up the plate
- UV light or locating agents
- reveals colourless chemicals on the plate
