Unit 2 Flashcards
1
Q
What is an Ester?
A
a family of organic compounds that are formed when an alcohol reacts with a carboxylic acid.
2
Q
What is the ester link?
A
COO
3
Q
How are esters formed?
A
by a condensation reaction (or esterification)
4
Q
What is the functional group for the hydroxyl group?
A
OH
5
Q
What is the functional group for the carboxyl group?
A
COOH
6
Q
In the ester link, what goes with the alcohol and what goes with the carboxylic acid?
A
CO - carboxylic acid
O - alcohol
7
Q
With what ending in the name can you identify an ester?
A
-oate
8
Q
When naming esters, what gives the first name and what does it become?
A
Alcohol gives the first name
- Alkyl
e. g methanol - methyl
9
Q
What ending does the second name form?
A
alkanoate
e.g ethanoic acid - ethanoate
10
Q
Features of an ester:
A
strong, sweet smell, often a fruity taste
11
Q
What ae esters used for?
A
solvents, fragrances or flavourings
12
Q
How can a condensation reaction be speeded up? (3)
A
- by heating the reaction mixture
- adding a catalyst
- adding concentrated sulfuric acid
13
Q
What does concentrated sulfuric acid provide?
A
hydrogen ions needed to catalyse the reaction
14
Q
What is hydrolysis?
A
a reaction in which a molecule is split up by a chemical action of water. The reverse of a condensation reaction
15
Q
What are edible fats and edible oils?
A
naturally occurring compounds that can be obtained from animal, vegetable or marine sources
16
Q
What are oils described as at room temperature?
A
liquids
17
Q
What are fats described as at room temperature?
A
solids
18
Q
When hydrolysed, what do fats and oils give?
A
Glycerol + 3 carboxylic acid molecules
19
Q
What is the structural name for glycerol?
A
propane-1,2,3-triol
20
Q
What are fatty acids?
A
unsaturated or saturated carboxylic acids, usually a long carbon chain, which are obtained from the hydrolysis of fats or oils
21
Q
what do oils decolourise and what does this indicate?
A
oils decolourise a bromine solutions to a much greater extent than fats and this indicates the degree of unsaturation is greater in oils
22
Q
What has a lower melting point; fats or oils?
A
oils
23
Q
what is hydrogenation?
A
addition of hydrogen atoms
24
Q
What do fats and oils supply the body with?
A
source of energy
essential fatty acids
25
Which two functional groups do amino acids contain?
- amino group NH2
| - carboxyl group COOH
26
When naming amino acids, which functional group goes in front?
amino group is places in front of the carboxyl group
27
Proteins are natural polymers formed by what?
condensation reactions
28
what kind of link do protein produce?
amide link (or peptide link)
29
What is the structure of the amide link?
O=C-N-H
30
When a large number of amino acids are condensed together, what does this form?
polypeptide
31
proteins are broken down into amino acids during which process?
digestion
32
What are essential amino acids?
amino acids which our body cannot synthesise/construct
33
What are the two types of proteins?
- fibrous proteins
| - globular proteins
34
What are the features of Fibrous proteins?
- tough and insoluble
- used to form skin and muscles
- long fibre-like structures
35
What are some features of Globular proteins?
- soluble in water
| - have spiral chains
36
What is the meaning of denatured?
when a protein loses its proper shape
37
How can enzyme activity be measured?
by counting the bubbles of oxygen produced in a fixed time
38
What happens when the hydrogen bonds break? (enzyme function)
causes the shape of the enzyme to change which leads to catalytic activity to be lost
39
How are soaps made?
the alkaline hydrolysis of fats/oils using sodium or potassium hydroxide
40
What is another name for alkaline hydrolysis?
saponification
41
What gives soaps its property?
structure an bonding of the negative ions
42
What is the property of soap?
to clean oil and grease
43
What are the two parts to sodium stearate (soap)??
head and a tail
44
What are the features of the "head"' in soap?
- carboxylate head (COO-NA+)
- ionic
- water soluble
- hydrophilic
45
What are the features of the "tail" in soap?
- long covalent hydrocarbon chain
- non-polar
- soluble in grease or oil
- hydrophobic
46
What does hydrophilic mean?
water liking
47
What does hydrophobic mean?
water repelling
48
What are all sodium and potassium compounds soluble in?
water
49
What are emulsions?
small droplets of one liquid dispersed within another
50
What is an emulsifier?
helps two immiscible liquid stay mixed, this prevents two layers from forming
51
How does an emulsifier work?
- has two parts with different solubility's; hydrophilic head (polar) and a hydrophobic tail (non-polar).
- polar head mixes with water whilst the non-polar tail mixes with non-polar solvents (oil)
- thus the differences in solubility of the two parts of the emulsifier prevents immiscible liquids from separating
52
What are essential oils described as?
hydrophobic liquids
53
What are essential oils?
concentrated extracts of the volatile non water-soluble aroma compounds from plant material
54
Which functional groups are found in essential oils?
esters, aldehydes, ketones and alcohols
55
Which process is used for the extraction of essential oils?
steam distillation
56
What are Terpenes?
a family of natural organic compounds that are a component in a variety of fruit and floral aromas.
57
What is an important component in essential oils?
Terpenes
58
What kind of compounds are Terpenes?
unsaturated compounds based on isoprene
59
What is the structural formula of a Terpene?
c5h8; 2-methylbuta-1,3-diene
60
Isoprene units can be linked to form which two structures?
- linear terpene
| - cyclic terpenes
61
What are linear terpenes?
joined 'head' to 'tail'
62
What are cyclic terpenes?
joined to form ring structures
63
Can terpenes be oxidised?
yes
64
Terpenes containing oxygen or other functional groups are known as what?
terpenoids
65
Give an example of a terpene:
Myrcene
66
What do many reactions require? and what are the reactions called?
- light to provide energy to allow the reaction to occur
| - Photochemical reactions
67
Examples of photochemical reactions:-
- photographic films
| - between an alkene and bromine
68
How do you calculate velocity?
velocity = frequency x wavelength
| V = f x λ
69
What is ultraviolet (UV) radiations?
a high-energy form of light
70
What are the 3 different UV lights?
- UVA
- UVB
- UVC
71
What is UVA light? (features)
- has the lowest frequency
- least energy
- results in aging of the skin (A for aging)
- Tanning beds
72
What is UVB light? (features)
- higher frequency
- more energy
- sunburn ( B for Burning )
- partly blocked by ozone layer
73
what is UVC light? (features)
- highest frequency
- shortest wavelength
- totally absorbed by the ozone layer
74
Exposure to UV light can result in what?
molecules gaining enough energy for bonds to be broken
75
What does damage to DNA cause?
mutations; which stops the DNA functioning properly
76
UVA and UVB cause wrinkles by what?
breaking down collagen
77
When wrinkles develop, this creates what?
substances called free radicals
78
How does sun block work?
containing organic and inorganic active ingredients
79
What are free radical scavengers?
molecules which can react with free radicals to form stable molecules and prevent free radical chain reactions
80
What name is given to the group "COO"?
carboxylate group
81
What does a cold paper towel around a test tube do when making an ester?
the cold surface reduces evaporation of the contents of the test tube by condensing the vapours
82
Why is a water bath used for heating esters and alcohols and not a Bunsen burner?
because esters and alcohols are flammable
83
What is the role of sodium hydrogencarbonate?
neutralises any unreacted acid producing a salt
84
What is the equation for a condensation reaction?
alcohol + carboxylic acid → ester + water
85
What does ⇌ mean?
reversible reaction
86
For complete hydrolysis of an ester, what is required?
a strong alkali and heating under reflux
87
What happens when you heat a protein?
the heat breaks the intermolecular bonds in the protein which causes the shape of the protein to change.
88
What do alcohols end their name in?
-OL
89
Alcohols based on the alkane structure are called what?
Alkanols
90
When numbering (naming) alcohols, what has priority?
-OH group
91
What are the three types of alcohols?
- primary alcohol
- secondary alcohol
- tertiary alcohol
92
What are primary alcohols?
no more than one carbon atom is joined directly to the carbon bonded to the -OH group
(-OH group is at the end on a chain)
93
What are secondary alcohols?
there are two carbon atoms bonded directly to the carbon bonded to the -OH group
(-2, 3-ol)
94
What are tertiary alcohols?
when there are three carbon atoms bonded directly to the carbon bonded to the -OH group
95
Cycloalkanols are examples of what kind of alcohols?
secondary alcohols
96
What are alcohols with two -OH groups called?
Diol; dihydric alcohols
97
What are alcohols with three -OH groups called?
Triol; trihydric
98
What are dihydric and trihydric alcohols used as?
high temperature polar solvents
99
What are oxidation of alcohols used to distinguish?
to distinguish between primary, secondary and tertiary alcohols
100
Which solutions is used to distinguish between alcohols?
- acidified potassium dichromate
| - copper (II) oxide
101
What is the colour change to primary and secondary alcohols when using acidified potassium dichromate?
orange -> blue/green
102
Primary alcohols can be oxidised into how many stages? and what are the names of the compounds made?
Two
| Aldehyde and carboxylic acid
103
What is the functional group of an aldehyde?
COH (H-C=O)
104
Within oxidation, where does the oxygen come from?
its supplied by an oxidising agent
105
Referring to ratio, how can you tell that oxidation has taken place?
increase in the O:H ratio
106
What is oxidation?
can take place by the loss of hydrogen from a molecule or by gain of oxygen
107
All of the oxidation products of a primary and secondary alcohol contain the C=O group which is known as what?
Carbonyl group
108
When you oxidise a secondary alcohol, what compound is formed?
Ketone
109
Why cant tertiary alcohols undergo mild oxidation?
because there is no hydrogen atoms bonded to the carbon atom
110
When naming an aldehyde, what goes at the end of the name?
-al
111
What is an alkanone?
a compound, which contains the carbonyl group at a position within the hydrocarbon chain
112
When naming a ketone, what goes at the end of the name?
-one`
113
What is an alkanoic acid?
a compound, which contains the carboxyl group at the end position of a hydrocarbon chain
114
What do acid molecules produce?
hydrogen ions H+
115
What is the equation for the breakdown of the carboxyl group?
carboxyl group → carboxylate ion + hydrogen ion
| -COOH -COO H+
116
What is the equation for neutralisation?
Alkali + acid → salt + water
117
When is a salt formed?
when the hydrogen ion from an acid is replaces by a metal ion
118
To identify if a reduction has taken place, in terms of Ratio what happens?
O:H ratio decreases
119
By undergoing oxidation, what do antioxidants provide?
electrons to prevent the oxidation of fats/oils in foods
120
What is a reducing agent?
causes reduction reactions to occur
121
What are free radicals?
are atoms or molecules, which contain unpaired electrons. Electrons have a very strong tendency to exist in a paired rather than an unpaired state, free radicals indiscriminately pick up electrons from other atoms, which in turn converts those other atoms into secondary free radicals, thus setting up a chain reaction which can cause substantial biological damage.
122
What can free radials break down?
strands of DNA
