Organic 1 Flashcards
(108 cards)
1
Q
What does nomenclature
mean
A
The system used for naming organic
compounds
2
Q
What does the term empirical
formula mean?
A
Simplest whole number ratio of atoms in
a molecule
3
Q
What does the term molecular
formula mean
A
It provides the actual number of atoms of
different elements in a molecule
4
Q
What does the term displayed
formula mean?
A
It shows every atom and every bond in a
molecule
5
Q
What does the term structural
formula mean
A
It shows the arrangement of atoms in a
molecule without showing every bond
6
Q
Define skeletal formula
A
A type of formula which is drawn as lines
with each vertex being a carbon atom.
Carbon atoms not drawn, assumed each
C atom has all unspecified bonds as C-H
7
Q
Define homologous series
A
A series of organic compounds having
the same functional group but with each
successive member differing by CH 2
8
Q
What is a functional group
A
A group of atoms responsible for
characteristic reactions of a compound
9
Q
Give the suffixes for:
a) No double bonds
b) At least one double bond
c) An alcohol
d) An aldehyde
e) A ketone
f) A carboxylic acid
A
a) No double bonds -ane
b) At least one double bond -ene
c) An alcohol -ol
d) An aldehyde -al
e) A ketone -one
f) A carboxylic acid -oic acid
10
Q
Give the prefixes for:
a) CH 3 group
b) C 2H 5 group
c) C 3H 7 group
d) C 4H 9 group
e) Cl group
f) Br group
g) I group
A
CH 3 group methyl-
b) C 2H 5 group ethyl-
c) C 3H 7 group propyl-
d) C 4H 9 group butyl-
e) Cl group chloro-
f) Br group bromo-
g) I group iodo-
11
Q
What is the general formula of
alkanes
A
C n H 2n+2
12
Q
What is the general formula of
alkenes
A
C n H 2n
13
Q
What does saturated mean?
A
Organic compounds which only contain
single bonds
14
Q
What are unsaturated
compounds
A
Organic compounds that contain at least
one carbon carbon double covalent bond
15
Q
Define structural isomerism
A
When molecules have the same molecular
formula but different structural formula
16
Q
What are the 3 ways in which
structural isomers can be
formed?
A
- Alkyl groups can be in different places
- Functional groups can be bonded to
different parts - There can be different functional groups
17
Q
What are stereoisomers
A
Organic compounds with the same
molecular formula but have different
arrangement of atoms in space
18
Q
What is E-Z isomerism and
how are the E and Z isomers
decided?
A
E-Z isomerism is caused by the limited rotation about C=C double bonds
If the two substituents with the highest atomic number are on the same side of the double bond, it is the Z (zusammen) isomer
If they are on different sides, it is the E (entgegen) isomer
19
Q
What is homolytic fission
A
It happens when each bonding atom
receives one electron from the bonded
pair forming two radicals
20
Q
What is heterolytic fission
A
When one bonding atom receives both
electrons from the bonded pair
21
Q
What are radicals
A
Highly reactive, neutral species
22
Q
How is a covalent bond
formed from two radicals?
A
The radicals collide and the electrons are
involved the bond formation
23
Q
What is an alkane
A
A saturated hydrocarbons containing
C-H bonds only
24
Q
How are alkane fuels
obtained
A
Alkane fuels are obtained from the
fractional distillation, cracking and
reforming of crude oil
25
Describe the process of
fractional distillation
The oil is pre-heated then passed into a column.
2. The fractions condense at different heights and the temperature of column
decreases upwards
3. The separation of the fuels depends on boiling point which depends on size of
molecules. The larger the molecule the larger the London forces
4. Similar molecules (size, bp, mass) condense together and so are collected at
the same fraction
5. Small molecules condense at the top at lower temperatures and big
molecules condense at the bottom at higher temperatures
26
What is cracking?
It is the process of converting large
hydrocarbons to smaller molecules by
breakage of C-C bonds
27
What is the reforming of
crude oil?
It is processing of straight-chain
hydrocarbons into branched-chain
alkanes and cyclic hydrocarbons for
efficient combustion
28
What is the shape and angle
of an alkane?
Tetrahedral
109.5Β°
29
Describe the π (sigma) bond in
alkane
The sigma bond is a covalent bond
which has a direct overlap of the electron
clouds of the bonding atoms
30
How reactive are alkanes
Very unreactive
31
What reactions will alkanes
undergo
Combustion and reaction with halogens
32
What type of reaction is
combustion
Oxidation reaction
33
What is complete combustion
Combustion that occurs with plentiful
supply of air
34
Write an equation for the
complete combustion of
octane
C 8 H 18 (g) + 12.5 O 2 (g) 8CO 2 (g) +
9H 2 O(l)
35
What are the products of
complete combustion when
alkanes are used
Carbon dioxide and water
36
What is the colour of the
bunsen burner flame during
complete combustion
Blue
37
What is incomplete
combustion and what products
are formed in the case of
alkanes
Combustion in a limited supply of oxygen
Products : water, carbon dioxide and
carbon monoxide
38
What type of hydrocarbon are
most likely to undergo
incomplete combustion?
Longer chains
39
What are the pollutants
formed in the combustion of
alkanes?
Carbon monoxide, oxides of nitrogen
and sulfur, carbon particulates and
unburned hydrocarbons
40
What is the environmental
impact of carbon monoxide?
It is toxic/poisonous
41
What is the environmental
impact of soot (carbon)?
Asthma, cancer, global dimming
42
What are the environmental
impacts of nitrogen oxides?
NO is toxic and can form smog
NO 2 is toxic and acidic and forms acid
rain
43
What are the environmental
impacts of unbranched
hydrocarbons
They contribute towards formation of
smog
44
What is the importance of catalytic
converter?
These remove CO, nitrogen and
unburned hydrocarbons (e.g. octane,
C8H18) from the exhaust gases, turning
them into less toxic products CO 2 , N 2
and H 2 O.
45
What are biofuels?
They are fuels developed from
renewable resources.
Alcohols and
biodiesel are two examples of renewable
plant- based fuels
46
What are the advantages of biofuels
Reduces of use of non-renewable
fossil fuels
- Use of biodiesel is more
carbon-neutral
- Fossil fuels can be used
feedstock for organic compounds
- Less large scale pollution
47
What are the disadvantages of biofuels
Less food crops may be grown
because crops for biofuel would
be grown instead
- Reduction of rain forests have
to be cut down to provide land
- Shortage of fertile soils
48
How are halogenoalkanes
formed from alkanes
Radical substitution
49
In the presence of what does
alkane react with halogens
uv
50
What are the three stages of
free radical substitution
Initiation - breaking halogen bond to form free radicals
Propagation - chain part of the reaction where products are formed but free radical remains
Termination - free radicals removed, stable products formed
51
What are the limitations of
free radical substitution?
If there is excess halogen further
substitution will take place therefore the
desired product will be harder to
separate from the others
52
What are alkenes
Unsaturated hydrocarbons that contain
at least one C=C bond made up of a π
bond and a π bond
53
How is a π bond formed
Electrons in the adjacent p orbitals
overlap above and below the carbon
atoms. They can only be made after a π
bond is formed
54
What bond restricts the
rotation of carbon atoms
π bond
55
What is the angle and shape
of a double bond
What is the angle and shape
of a double bond
56
What is the qualitative test
for alkanes
Bromine water (Bromine dissolved in water)
Orange to colourless
57
Are alkenes more or less reactive
than alkanes
More reactive
due to high electron
density of double bond and the fact the
pi-bond is slightly easier to break
58
What intermolecular forces of
attraction do they have
London forces only
59
What are the types of isomers
that can be formed using
alkenes
E/Z isomers - due to the restricted
rotation
60
What is an electrophile
Species that are electron pair acceptors (and are attracted to electron rich areas)
61
What is the most stable type of
carbocation intermediate?
Why?
Alkyl groups have a positive inductive
effect, so the most stable carbocation is
the one bonded to the most other carbon
atoms
62
Major products will be formed
from which kinds of
carbocations
Tertiary (or the most stable available)
63
Reaction from alkene to alcohol?
Steam in the presence of an acid catalyst,
usually phosphoric acid
Reaction is called hydration
Electrophilic addition
64
What conditions are needed
for the electrophilic addition of
a hydrogen halide to an
alkene
RT
65
What is the reaction called
when a halogen is added to
alkene
Halogenation
66
How does a molecule with a non-polar bond react as if it is an electrophile
C=C double bond with a high electron
density induces a temporary dipole in the
halogen molecule β Ξ΄+ atom attracted
to double bond
67
How can an alkene be
converted into alkane? What is
the reaction called and what
are the required conditions?
Hydrogenation
Conditions β 150Β°C, nickel catalyst
68
What is an addition polymer?
Many monomers bonded together via
rearrangement of bonds without the loss
of any atom or molecule
69
What are monomers? What form do they usually take
Molecules which combine to form a
polymer
Usually have a C=C bond which breaks
to leave a repeating pattern
70
What are the ways in which
plastics can be disposed
L
C
E-G
R
R
O-F
β Landfill
β Combustion
β Electricity generation
β Reuse
β Recycle
β Organic feedstock
71
What are the disadvantages of
recycling
β Plastics must be sorted into different types
β Expensive
β Labour intensive
β Requires high technology
72
How can chemists limit the
problems caused by
polymer disposal
Developing biodegradable polymers
- Removing toxic waste gases caused
by incineration of plastics
73
Explain what happens in
organic feedstock
Plastics are separated and broken down into
small organic molecules through a series of
reaction. The molecules can then be used
produce plastics and in other industries
74
What are halogenoalkanes?
Saturated organic compounds that
contain carbon atoms and at least one
halogen atoms
75
Are halogenoalkanes soluble
in water
not enough energy released from interaction with H20 to break H bond between H20 molecules.
76
Do halogenoalkanes have a
polar bond? Why
Yes
77
When would haloalkanes have higher
boiling points
Increase Carbon chain length
Halogen further down group 7
As chain length increases the contribution from permanent dipole interactions less significant.
77
What type of intermolecular
forces do halogenoalkanes have? Why?
Permanent dipole-dipole and London
forces of attraction
C-X bond polarity creates permanent
dipoles
78
What is the most important
factor in determining haloalkane
reactivity
The strength of carbon halogen bond
79
What is the trend in reactivity of primary, secondary and tertiary haloalkanes
β The tertiary halide produces a precipitate almost instantly.
β The secondary halide gives a slight precipitate after a few
seconds.
β The primary halide takes considerably longer to produce a
precipitate
80
Define nucleophile
Electron pair donor
81
What is nucleophilic
substitution
A reaction where a nucleophile donates
a lone pair of electrons to Ξ΄+ C atom, Ξ΄β
atom leaves molecule (replaced by
nucleophiles)
82
What is hydrolysis?
A reaction where water is a reactant
83
What reactant often produces
hydroxide ions for hydrolysis?
What reactant often produces hydroxide ions for
hydrolysis?
Water
84
What fission does water undergo to produce OH-
Heterolytic fission
85
What are the conditions/
reactants needed for the
elimination reaction of
haloalkanes
NaOH or KOH dissolved in ethanol (no water
present)
Heated
86
What is formed in the
elimination reaction of
haloalkanes
An alkene, water and halogen ion
87
How can you convert a
haloalkane into an amine
Reagent: NH 3 dissolved in ethanol
Conditions: Heating under pressure in a sealed tube
Mechanism: Nucleophilic Substitution
Type of reagent: Nucleophile - ammonia
88
How do you convert
halogenoalkane into
alkene?
what does the Oh ion act as
Use ethanolic potassium hydroxide to produce
alkenes (where the hydroxide ion acts as a base
89
How do you produce nitriles
from haloalkane
Use potassium cyanide to produce
nitriles (where the cyanide ion acts as a
nucleophile
90
How can you compare the
rate of hydrolysis of
haloalkanes?
Aqueous silver nitrate is added to a halogenoalkane and a silver halide
precipitation is formed. The quicker the precipitate is formed the faster the rate of
hydrolysis.
AgI (s) - yellow precipitate
AgBr(s) β cream precipitate
AgCl(s) β white precipitate
91
What is the functional group of
an alcohol?
Hydroxyl group -OH
92
What is the general formula of
an alcohol?
C n H 2n+1 OH
93
What kind of intermolecular
forces do alcohols have?
Why?
Hydrogen bonding, due to the
electronegativity difference in the OH
bond
94
How do alcoholsβ melting point
and boiling point compare to
other hydrocarbonsβ of similar C
chain lengths? Why?
Higher, because they have hydrogen
bonding (strongest type of intermolecular
force) β stronger than London forces
95
Are alcohols soluble in water?
Why does solubility depend on
chain length
Soluble when short chain - OH hydrogen bonds
to hydrogen bond in water
Insoluble when long chain - non-polarity of C-H
bond takes precedence
96
What forms if you partially
oxidise a primary alcohol?
Conditions?
An aldehyde
Dilute sulphuric acid, potassium
dichromate (VI), distill product as itβs
produced, gentle heating
97
What forms if you fully oxidise
a primary alcohol
Conditions?
A carboxylic acid
Concentrated sulphuric acid, potassium
dichromate (VI), reflux, strong heating
98
What forms if you oxidise a
secondary alcohol?
Conditions?
Concentrated sulphuric acid, potassium
dichromate (VI), strong heating
99
Is it possible to oxidise tertiary
alcohol?
No.
100
What is a dehydration
reaction
A reaction where water is lost to form an
organic compound
101
What are the products of
dehydration reaction of alcohol
and the conditions needed
Alkene and water
Concentrated sulfuric acid or
concentrated phosphoric acid and 170Β°C
102
How can you produce
chloroalkanes from
alcohols
Use PCl 5 ( PCl3 / conc HCl / SOCl2 / mixture of NaCl
+ H2SO4 can all also be used for substituting a Cl
103
How can you produce
bromoalkanes from
alcohols?
Use 50% concentrated sulfuric acid and
potassium bromide
104
How can you produce
iodoalkanes from alcohols?
Use red phosphorus and iodine
105
What is formed when reacting alcohol with PCl5
R-Cl + POCl3 + HCl
106
Reaction of iodoalkanes
PI3 (formed insitu) + 3R-OH -> 3R-I + H2PO3
107
How do you prepare and
purify of a liquid organic
compound?
1. Heat under reflux
2. Extract with a solvent in a separating funnel
3. Distill
4. Dry with an anhydrous salt
5. Determine boiling temperature
