Organic Chemistry Flashcards
1
Q
Functional group
A
An atom or group of atoms which is responsible for the characteristic properties of a series of organic compounds
2
Q
Substitute reaction
A
A chemical reaction in which an atom or group of atoms in a molecule is replaced by another atom or group of atoms
3
Q
Mechanism for substitute reaction
A
free radical substitution
initiation (homolytic fission)
propagation
termination
4
Q
Addition reaction
A
- A chemical reaction in which two substances react together forming a single substance
- Only happens to unsaturated compounds
5
Q
Mechanism for addition reaction
A
ionic addition
apparoach/polarisation/heterolytic fission/carbonium ion/ product formation
6
Q
Polymers
A
long chain molecules made by joining together many small molecules called monomers
7
Q
Elimination reaction
A
one in which a small molecule is removed from a larger molecule to leave a double bond in the larger molecule
8
Q
Organic synthesis
A
The process of making organic compounds from simpler starting materials
9
Q
Chloroalkane
A
a compound in which one or more of the hydrogen atoms in an alkane molecule have been replaced by chlorine atoms
10
Q
Example of a chloroalkane
A
chloroform (CHCL₃)
11
Q
Use of chloroalkanes
A
- As solvents for removing oil + grease marks from machinery
- In dry cleaning of clothes - remove substances without harming the fabric
12
Q
Examples of chloroalkanes
A
Monochloromethane
Dichloromethan
Trichloromethane (chloroform)
Tetrachloromethane
1-Chloropropane
1,2-dichloropropane
1,1,1-trichloroethane
13
Q
Chloroalkane notes
A
have same basic tetrahedral shape as corresponding alkanes
not a hydrocarbon - contains Cl
14
Q
Physical properties of chloroalkanes
A
- Solubility: do not dissolve in water, readily dissolve with non-polar solvents eg. cyclohexane, methylbenzene
- Physical state: liquids at room temp
15
Q
Polar
A
dissolves in water
16
Q
Non-polar
A
needs an organic solvent
17
Q
Alcohols functional group
A
-OH group (the hydroxyl/hydroxide group)
18
Q
General formula of alcohols
A
Cₙ H₂ₙ₊₁ OH
19
Q
Naming alcohols
A
change the -e ending to -ol
eg. methane –> methanol
20
Q
Examples of alcohols
A
methanol (methyl alcohol) ethanol (ethy alcohol) propan-1-ol propan-2-ol butan-1-ol
21
Q
Classifications of alcohols
A
primary
secondary
tertiary
22
Q
Primary alcohol
A
one where carbon atom joined to the -OH group is attached to only one other carbon atom
23
Q
Secondary alcohol
A
One where the carbon atom joined to the -OH group is attached to two other carbon atoms
24
Q
Tertiary alcohol
A
one where the carbon atom joined to the -OH group is attached to three other carbon atoms
25
Ethanol
ethanol for alcoholic drinks is produced by a process known as fermentation
26
Glucose fermenting equation
C₆H₁₂O₆ --(yeast)--> 2C₂O₅OH ₊ 2CO₂
27
Methanol property
particularly toxic
28
Use of methanol
added to industrial alcohol to prevent people from drinking it (used as a denaturing agent)
29
methylated spirits
mixture which consists of approx. 90% ethanol and 10% methanol
30
ethanol's effects on the body
1. Relax muscles, loosening inhibitions
2. V. toxic chemical if taken in large quantities (ethanol poisoning)
3. Excess - cause unconsciousness, vomitting. Can lead to death (drowning in vomit) + liver failure
4. Depresses activity of the central nervous system - shows reaction time, makes us less vigilant, impairs judgement
31
uses of ethanol
- Used in alcoholic drinks
- Main use as a fuel
- Used as a solvent
- Used in perfumes, after-shave lotions, deodorants, hair sprays
32
physical properties of alcohols
- Boiling points: alcohols have higher boiling points than corresponding alkanes (effect of hydrogen bonding)
- Solubility in water: methanol, ethanol, propan-1-ol are completely miscible w/ water (infinitely soluble). Solubility decreases w/ length of carbon chain.
Higher alcohols ave poor solubility in water + readily dissolve in solvents eg. cyclohexane
33
miscible
mix with
34
absolute alcohol
pure ethanol
35
aldehydes functional groups
contain the -CHO functional group
36
aldehydes general formula
Cₙ H₂ₙ₊₁ CHO
37
aldehydes naming
named from parent alkane by changing -e ending to -al
| eg. methane becomes methanal
38
placement of functional group in aldehydes
adlehyde functional group must always occur at end of the carbon chain
39
carbonyl group
- the carbon connected to the O by double bond is called the carbonyl group
- The carbonyl group + atoms it is bonded to all lie in one plane w/ all bond angles of 120 degrees
40
examples of aldehydes
methanal (CHCHO) - formaldehyde
ethanal (CH3CHO) - acetaldehyde
propnanal (C2H5CHO) - propioaldehyde
butanal (2 isomers)
41
physical properties of aldehydes
-Boling points:
•Methanal - gas at room temp
•Ethanal - v. volatile liquid
-Solubility - solubility in water decreases w/ length of carbon chain. All aldehydes are quite soluble in organic solvents. Lower members of aldehyde - v soluble in water
42
volatile
Unstable
43
use of aldehydes
- Methanal - used for preserving biological specimens + as embalming fluid
- Main use of benzaldehyde is as a flavouring agent in cooking
44
benzaldehye
benz + aldehyde
45
ketones functional groups
>C=O functional group (Attached to two alkyl groups)
46
ketones general formula
RCOR'
47
Difference between aldehydes + ketones
Diff. in structural formula is the replacement of the hydrogen atoms in aldehydes by an alkyl group, R'
48
examples of ketones
propanone (Acetone)
| butanone (methylethyl ketone)
49
alkyl
w/o one hydrogen atom
50
naming ketones
change final -e of parent alkane to -one
eg. propane - propanone
51
example of a ketone + its use
propanone
used as an organic solvent, eg. nail varnish remover
52
physical properties of ketones
-Have higher boiling points than corresponding alkanes
-Solubility: Lower members - v soluble in water, eg. propanone + butanone completely miscible w/ water
C5+ not soluble in water
53
uses of propanone + butanone
widely used as solvents in industry - cna act as solvents for both polar + non-polar substances
54
carboxylic acids functional groups
Contain the carboxyl group, -COOH
55
carboxylic acids general gormula for aliphatic monocarboxylic acids
Cₙ H₂ₙ₊₁COOH or RCOOH
| R is an alkyl group
56
carboxylic acids naming
named from parent alkane by changing -e ending to
| -oic acid
57
carboxylic acids examples
methanoic acid
Ethanoic acid
propanoic acid
58
methanoic acid
found in stings of nettles + ants
59
ethanoic acid
used to make cellulose acetate, used in varnishes, lacquers, rayon (a type of textile)
60
propanoic acid
inhibits growth of mould + used as food preservative
61
benzoic acid
used as food preservative, in antiseptic medicines, as a fungicide for treating skin problems (eg. ringworm + athelet's foot)
62
carboxylic acids properties
have characteristic odours
63
carboxylic acids physical properties
- Ethanoic acid is liquid at room temp, solid at 17°C
- Methanoic, ethanoic, propanoic, butanoic acid are all liquids at room temp + completely soluble in water
- Solubility: in water, decreases w/ increasing length of the carbon chain
- Higher members more soluble in organic solvents eg. cyclohexane
64
glacial acetic acid
pure ethanoic acid is often referred to as glacial acetic acid as the solid material looks like ice
65
Esters functional group
-COO- group
66
Esters general formula
RCOOR'
67
Esters & carboxylic acids
Esters may be considereds as being derives from carboxylic acids by replacing te H of the -OH group by an alkyl group
68
Condensation reaction
A chemical reaction in which two molecules combine to form a larger molecule w/ loss of a smaller molecule such as water
69
Examples of Esters
Methyl1methanoate
Methyethanoate
Ethylmethanoate
70
Esters physical properties
- Lower members are volatile liquids w/ pleasant fruit smells
- Low boiling points
- Solubility: lower members - soluble in water, solubility in water decreases as length of carbon chain increases. Soluble in organic solvents.
71
Esters uses
- commonly used in fruit flavourings + in manufacture of perfumes and cosmetics
- used as solvents for varnishes + spray paints + also as solvent in some perfumes
72
polyester
consist of millions of ester molecules linked together
73
bonding in benzene/aromatic compounds
contain a benzene ring structure in their molecules
74
properties in benzene
all carbon-carbon bonds in benzene ring are identical + are intermediate in length between a double + single bond
75
Sigma bonds in benzene
- Carbon atom has four electrons in its outer shell,
- Of these four, each carbon atom uses three of them to form sigma (σ) bonds by head-on overlap if atomic orbitals
- Two of these single, sigma bonds are formed between each carbon atom + two adjacent carbon atoms
- Third sigma bond formed w/ an atom of hydrogen
76
bond angles in benzene
120 degrees
77
orbitals
- Remaining electron in outer energy level of each carbon atom is in a p orbital
- These six singly-occupied p orbitals overlap sideways to form two doughtnut-shaped electron clouds
- Pi bond is more correctly referred to as a pi-bonding system
78
delocalised electrons
6 electrons in the pi bond do not belong to any particular atom. These are described as six delocalised electrons.
Delocalisation of electrons explains why alternating double + single bonds do not exist in benzene. Give extra stability.
79
Summary of important points about chemical bonding in benzene molecule
- All c-c bonds are identical, ie. c-c single covalent bonds containing a shared pair of electrons. May be described as sigma bonds formed by head-on overlap of singly-occupied atomic orbitals
- All c-c bonds intermediate in length between c-c single bonds + c=c double bonds
- 6 singly-occupied p atomic orbitals overlap sideways to form a pi bonding system containing six delocalised electrons
- C-H bonds are all identical single convalent bonds containing a shared pair of electrons. These bonds may also be described as sigma bonds formed by head-on overlap of singly-occupied atomic orbitals
80
properties of benzene
- Benzene is a planar molecule
- Non-polar
- Carcinogenic
81
uses of benzene
Many aromatic compounds are not dangerous despite benzene being carcinogenic. They form basis of many pharmaceutical compounds, dyes, detergents, insectides, herbicides, disinfectants
82
Uses of benzene in insecicides + hebicides
Napthalene (found in mothballs)
83
Uses of benzene in Dyes
2-amino-4-nitrophenol (yellow hair colourant)
84
Uses of benzene in narcotics
Cocaine
| Heroin
85
Uses of benzene in food flavourings
Vanillin (vanilla)
86
Organic Natural Products - examples
```
Benzaldehyde (in almonds)
Caffein (In tea + coffee)
Nicotine (in tobacco)
Opium (in poppies)
Limonene (in orange peel)
Penicillin (in bread mould)
```
87
test to show ethene is unsaturated
- add a few drops of bromine water to ethene in a test tube + shake well
- will turn brown Br water colourless
88
organic synthesis table
learn off
