AS organics Flashcards
(99 cards)
1
Q
homologous series
A
a series of organic compounds containing the same functional group with sucessive members differing by -CH2
2
Q
functional groups
A
a group of atoms responsible for the characteristic reactions of a compound
3
Q
alkyl group
A
-CH3
4
Q
aliphatic
A
carbon joined to each other branched (straight), unbranched or non-aromatic rings
5
Q
alicyclic
A
carbon joined in rings
(with or without branch)
6
Q
aromatic
A
some/ all carbons found in a benzene ring
7
Q
unstaurated
A
contain C=C or C≡C
8
Q
structural isomers
A
same molecular formula but different displayed formulae
9
Q
What is the naming system for compounds
A
Nomenclature
10
Q
Steps to naming organic compounds
A
- find longest unbranched backbone
- Add suffix for main functional group
- Number the functional groups and/or alkyl side chains
11
Q
prefix of alcohol
A
hydroxy-
12
Q
suffix of aldehyde
A
-al
13
Q
suffix of ketone
A
-one
14
Q
stems (from 0-10)
A
- meth-
- eth-
- pro-
- but-
- pent-
- hex-
- hept-
- oct-
- non-
- dec-
15
Q
Homolytic
A
Each bonding atoms recieves one electronforming 2 radical
16
Q
Hetrolytic
A
One of the bonding atoms recieves both electrons To form a cation and an anion
17
Q
Radical
A
a reactive species with an unpaired electron
(but not charged)
18
Q
Electrophile
A
(+ve) electron-deficient species , accepts electrons to form covalent bonds
19
Q
Nucleophile
A
(-ve)electron-rich species, provides pair of electron to form covalent bonds
20
Q
General formula of alkanes
A
CnH2n+2
21
Q
what is the type of bond in alkanes
A
sigma bonds
22
Q
How are sigma bonds formed?
A
The overlap of the s-orbitals
23
Q
Why are alkanes non-polared molecules?
A
- electronegativity diff. between C - H are neglegible
- bonds are relatively non-polared
24
Q
Structure of alkanes and its bond angles (why?)
A
Tetrahedral (109.5)
25
Factors affecting boiling point and (why?)
1. Chain length
(↑C = ↑ S.A. = ↑ London forces)
(↑electron = ↑strength of london forces)
2.Branching
↑ branching = ↓ surface contact = ↓ london forces
26
Why is Alkanes unreactive
1. ↑ bond enthalpy of C-C + H-H
2. ↓ polarity of sigma bond
27
What must be present for free-radical substituition
UV light
28
Three steps of free radical substitution
1. initiation
2.propagation
3.termination
29
Describle **initiation** of free radical substitution
Halogen molecules broken down in **Homolytic** fission, under UV
30
Describle propagation of free radical substitution
1. radical attacks alkanes
2. C-H bonds **Homolytic fission** occurs
3. alkyl radical formed attacks halogen molecules
4. forming haloalkane + halogen radical
31
Describle termination of free radical substitution
Two radical reacts together to form a single unreactive molecule
32
3 limitation of free radical substitution
1. impurities in the product
2. further substitution (when excess halogen under UV)
3. substitution on different carbon (cannot control where hetrolytic fission occurs)
33
Two bonds in alkenes
σ and π
34
one characteristic of π bond
Fixed above and below the planar, prevent rotation of the molecule
35
Bond angles of alkene
120 - trigonal planar
36
How does E/Z isomer work ?
E - piority group on **EPPOSITE** side of plane
Z- piority group on **ZAME** side of plane
37
What is the CIP priority rules ?
1. calculate the total atomic no of group
2. Group with greatest atomic no is the priority group
38
4 types of alkene reactions
1. hydrogenaton
2. Halogenation
3. hydrohalogenation
4. hydration
39
what does hydrogenation form
alkane
40
what type of reaction are the reactions of alkene?
electrophilic addition
41
Observation of halogenation (Bromine)
orange to colourless
42
What does hydration form ?
Alcohol
43
Inductive effect
↑ C-C bonds
carbocation ↓ +ve charged
↓ reactive
44
What does the Markownikoff's rule apply to ?
Only for **assymterical** molecules only
45
State Markownikoof's rule
Rules favours **major **product here:
Halogen (HX) / most electronegative halogen
bonds to
MOST SUBSTITUITED CARBON
46
Major product of the reaction (hydrogen halide)
halogen to
higher class carboncation
47
Major product of the reaction (interhalogen)
↑electronegative halogen to
↑ stable carboncation
48
Minor product of the reaction (interhalogen)
less electronegative to
more stable carbocation
49
Define polymers
A large chain formed from many thousands of repeat units of smaller molecules
50
Define monomers
A small molecule that conbines with many other monomers to form a polymers
51
Repeating units
the smallest group of atoms that connected after the other make up the polymer chain
52
3 polymers waste managements
1. recycling
2.combustion
3.feedstock recycling
53
What is feedstock recycling ?
polymers are broken down by chemical and thermal processes to form gases and fuel
54
4 types of alternative plastic solution
1. Bioplastic - made from cellulose, starch...
2. Biodegradable - breaks down naturally
3. Compostable - made from plants + degrade naturally
4. Photodegradable - break down under visible radiation
55
How are photodegradable polymers made
* Contains bonds that are weakened by absorbing light-
* can be an additive mixed into polymers to promote degradation
56
General formulae of alcohol
CnH2n+1 OH
57
Intermolecular forces involved in alcohol
1. Hydrogen bonding - when oxygen (δ-)from one molecules attracts a hydrogen (δ+) on another alcohol
2. Temporary D-D forces - ↑ chain = ↑ B.P.
58
Solubility of alcohol
1. Small alcohol dissolves in water
2. ↑ chain length= ↓ soluble
(As ↓ polared = ↓ likely to dissolve in polared solvent)
59
4 types of reaction of alcohol
1. Combustion
2. Oxidation
3. Dehydration
4. Substitution
60
# Alcohol reactions
What are the three types of oxidation reactions? + reagents?
primary in distill = aldehyde
primary in reflux = carboxylic acid
secondary in reflux = ketone
61
What is the colour change of oxidation reaction of alcohol
Orange to green
62
2 types of Haloalkane reaction
1. nucleophilic substitution
2. elimination
63
Reactivity of haloalkane
| (3 points)
1.↓electronegative down the group
2. ↓Polared bonds
3.↓bond enthalpy
4. ↓energy required to overcome
[↓ chain = more electronegative overall]
64
2 ways of hydrolysis of haloalkane
1. by aq. alkali
2. by water (with prescence of ethanol)
[both forms alcohol and halide]
65
Purpose of alcohol for hydrolysis by water
To enable the haloalkane organic layer to mix with water solvent
(haloalkane=non-polared, water=polared)
so won't mix
66
1. How to test for halide ions formation
2. Explain the reactivity of haloalkane?
(quickest = iodoalkane)
(second = bromoalkane)
(slowest = chloroalkane)
... to form p.p.
1. Add silver nitrate
(first to form p.p. = most reactive)
2. Iodoalkane is the most reactive
* least electronegative
* weakest bond C-I
* requires the least energy to overcome
67
Describle the environmental concern of organohalogens
| (2 points)
1. produces halogen radicals under UV
2. which catalyses the break down of Earth's protective ozone layer
68
2 example of organohalogens
CCl3F, CCl2F2
69
Eq. of halogens radical from organohalogens (which starting molecule = CF2Cl2)
CF2Cl2 -> CF2Cl* + *Cl
70
5 main organic techniques
1. distillation
2. heating under reflux
3. redistillation
4. BP determination
5. Drying
71
Purpose of distillation
To seperate liquids with different BP
72
4 steps of distillation
1. heat in round bottom flask
2. lowest B.P. evaporates first
3. pass through the condenser
4. fraction then collected in a seperate flask
73
Purpose of reflux
to enable reaction to fully complete
74
Steps to heating under reflux
1. continuously heat content
2. liebig condenser to ensure all vapour condense
3. So no reactant can escape via evaporation
75
What is redistillation ?
subsequent distillation carried our to obtain **purer** product
76
Purpose of boiling point determination
To compare to databook value as a measure of purity
77
4 steps to boiling point determination
1. tightly pack the substance into capillary tube
2. place into machine
3. record the MP and the range
4. compare to databook value
78
Two examples of drying agents for drying
Any anhydrous salt
(e.g. MgSO4 , CaCl2)
79
4 factors to determine synthesis routes
1. type of reaction - % yield
2. Reagent used - renewable ?
3. By-product , harmful/ toxic ?
4. Catalyst - Rates , cost
80
How to test for 1* /2* alcohol ?
Add potassium dichromate result: orange -> green
81
How to test for aldehyde ?
Add tollen's reagent Result : colourless -> dark silver p.p) MIRROR EFFECT
82
Test for haloalkane
Add silver nitrate and ethanol Result :
white p.p. = chloroalkane
creamy p.p = bromoalkane
yellow p.p = iodoalkane
83
What is Infrared spectrometry ?
1. IR radiation causes covalent bonds to vibrate and abosrb energy
2.The spectrum of absorption can be used to determine functional groups
84
What + Where is the fingerprint region ?
to determine exact molecules
< 1500 cm-1
85
Environmental impact of IR radiation
1. Atomospheric gas (e.g. CO2, H2O , CH4) aborbs IR radition
2. exacerbates global warming
3. emission usually from fossil fuel usage
86
Application of IR radiation
1. monitor gases that cause air pollution
2. modern breathalysers to measure ethanol
87
Define Time of Flight in mass spec
time for each ion to reach detector
88
Steps of mass spec
1. Sample is vapourised and pass through high voltage
2. Accelerated by -ve charged plates
3. deflected by magnetic field
4. reach detector to form spectrum
89
3 main peaks to focus on mass spec
1. Molecular peak - second rightmost peak (tells molecualr mass )
2. M+1 peak - right most peak (mass of compound with Carbon -13 isotopes)
3. framgent peaks - any peaks < RFM (fragment ions of the molecule detected)
90
# Markownikoff's rule
What does it means by most-substituted carbon
carbon where it has the most no. of H replaced by C.
i.e. highest class carbon
91
# Markownikoff's rule
Why does higher class carbocation more stable?
1. carbon bonded to more C
2. non-polared bonds = more stable
3. ↓ +ve carbocation
4. ↑ stable (as ↓ likely to react)
92
# Markownikoff's rule
Why does the more stable carbocation forms major product?
1. more likely form
2. as ↓ likely to be attacked
3. less energy needed to form
93
2 eq for the breakdown of ozone
94
3 condition of hydrogenation
1. 200 °C
2. 1000 KPa
3. Nickel catalyst
95
2 condition for hydration
1. 300 °C - reflux
2. sulfuric / phosphoric acid
96
What bonds do C in C=C make
2 σ with hydrogen
1 σ in C=C
1 π in C=C
97
Where are σ bonds found
1. C-H bond (1)
2. C-C bond (1)
3. C=C bond (1)
98
Optical isomerism
Non-superimposed mirror image
99
What is the difference between esterification and acid hydrolysis
Esterification - conc
Acid hydrolysis - diluted
