Unit 2 Flashcards
(181 cards)
1
Q
How are esters formed
A
A condensation reaction between an alcohol and a carboxylate acid
2
Q
What is the reaction creating waters called
A
Esterification
Condensation
3
Q
Finish the reaction
Alkanol + alkanoic acid —–>
A
Ester + water
4
Q
For which compounds are the H20 taken from in esterification
A
H from alkanol
OH from alkanoic acid
5
Q
What is the name of an esters functional group
A
Ester group
Ester linkage
6
Q
What is the ending to the name of an ester
A
Oate
7
Q
Describe where the name of an ester comes from
A
First part comes from the name of the alcohol
The second part comes from the name of the carboxylic acid
8
Q
Which to compounds create methyl butanoate
A
Methanol and butanoic acid
9
Q
Describe some of the properties of an ester
A
Strong sweet smelling
10
Q
What are esters used for
A
Fragrances
Flavourings
Solvents
11
Q
Are esters polar or non polar
A
They are not very polar
12
Q
Can ester dissolve in water
A
No
13
Q
Are the bp of esters high or low
A
Low
14
Q
Are esters organic
A
Yes
15
Q
Which two functional groups do alcohols and carboxylic acid join by to make an ester
A
Hydroxyl group of the alcohol and the carboxyl group of the acid
16
Q
What is a condensation reaction
A
A reaction which two reactant molecules join with the elimination of a small molecule which is usually, but not always, water
17
Q
Is condensation reversible
A
Yes
18
Q
What catalyst can be added to esterification
A
Concentrated sulphuric acid
19
Q
Why is concentrated sulphuric acid a good catalyst for an esterification reaction
A
It provides hydrogen ions and absorbs the water formed in the reaction and so encourages more alcohol and carboxylic acid to react
20
Q
What is the process which esters are broken down
A
Hydrolysis
21
Q
What catalyst can be used to hydrolyse esterification
A
Sodium hydroxide + heat
22
Q
What is a hydrolysis reaction
A
A reaction where a molecule reacts with water and breaks down into smaller molecules
23
Q
Edible fats and oils are ………. occurring compounds
A
Naturally
24
Q
Name the tree different sources of fats and oils
A
Animal
Vegetable
Marine
25
Edible fats and oils are esters
| True or false
True
26
How are fats and oils made
Condensation reactions between the alcohol glycerol and carboxylic acids fatty acids
27
What is the name of a compound with three hydroxyl groups
A triol
28
What is the systematic name for glycerol
Propane-1,2,3-triol
29
What happens to the name of an alcohol when it contains two or more hydroxyl groups
The parent alkane name is used in full (including the -e)
30
What are fatty acids
Straight chain carboxylic acids
31
What is an unsaturated compound
Compounds that contain at least one C=C
32
Fatty acids can only be saturated true or false
False
33
How many fatty acids will glycerol condense with
3
34
What's an ester formed from glycerol called
A glyceride
35
What are the esters in fats and oils called
Triglycerides
36
Which decolourises bromine quicker fats or oils
Oils
37
What does a fast reaction with bromine indicate
A degree of unsaturation
38
What states are fats and oil usually at room temperature
Oils are usually liquid and fats are usually solid
39
Why do oils have a lowering mp than fats
They have more c=c which distorts their shape and therefore molecules cannot pack closely together and so LDF between oil molecules are weaker
40
What are the uses of fats to our bodies
Concentrated source of energy which is more a long term energy source
Transport and storage of fat soluble vitamins
Supply the body with essential fatty acids
41
Where are proteins found
In all living cells
42
What are proteins used for in the body
Major structural materials
Enzymes
Hormones
(Maintenance and regulation of life processes)
43
What are proteins made of
Amino acids
44
How many amino acids are there
20
45
What elements do amino acids contain
Hydrogen
Nitrogen
Carbon
Oxygen
46
What is the amino group
NH3
47
What two functional groups do amino acids contain
Amino group
| Carboxyl group
48
What is a carboxyl group
COOH
49
What is the name of the reaction in which proteins are made from amino acids
Condensation
50
How do amino acids link together
The carboxyl group of one amino acid molecule and the amino group on the neighbouring amino acid molecule join together with the elimination of water
51
What is the amide/peptide link
```
I
C=O
I
N-H
I
```
52
What is the name of the molecule when three amino acids are condensed together
Tripeptide
53
What is the name of the molecule when a large number of amino acids condense
Polypeptide
54
What is the full name of the reaction forming proteins
Condensation polymerisation
55
What happens to proteins during digestion
They are broken down into amino acids
56
How are proteins broken down
React with water and undergo hydrolysis
57
Plants cannot synthesise all the amino acids that they need
| True or false
False
58
What are essential amino acids
Amino acids which cannot be synthesised by animals
59
How do animals obtain essential amino acids
By hydrolysing the plant or animal proteins that we eat
60
During digestion where do the hydrolysed proteins go?
The amino acids pass into our blood stream and are carried to various sites in our bodies where they reassemble into specific proteins that we need
61
What percentage roughly of amino acids are essential amino acids
50%
62
Where in our bodies can flavours be detected
Tongue and nose
63
What are humans basic tastes
```
Sweet
Sour
Bitter
Salty
Savoury
```
64
How does the nose detect flavourings
Smells and aromas when gaseous molecules from volatile molecules trigger receptors in the nose
65
What does the volatility of a compound depend on
The strength of the intermolecular forces
66
If intermolecular forces are weak the molecule will be more volatile
True or false
True
67
Describe the bp of a very volatile compound
Very low
68
What flavour is limonene responsible for
Oranges
69
The presence of hydroxyl groups suggest what type of bonding
Hydrogen bonding
70
Does presence of a hydroxyl group indicate polarity
Yes
71
The presence of functional groups suggests the presence of what attractions
Permanent dipole- permanent dipole
72
What volatility will compounds that are hydrogen bonded have
Less volatile
73
What influences what a food is cooked in
The presence of functional groups
Their solubility
So that the flavours do not escape
74
What should a polar flavouring be cooked in
Oil
75
What should a non polar flavouring be cooked in
Water
76
What is the polarity of peptide links
Polar
77
Name two types of protein and give an example of each
Fibrous- collagen
| Globular- enzymes
78
What determine the temperature that meat is cooked at
How much protein is found in the tissues
79
Why do different meats need to be cooked at different temperatures
To retain their different textures
80
What bonds of proteins does heat break
Hydrogen bonds keeping their shape
81
What is the name given to proteins which have been damaged whilst heating
Denatured
82
What are common flavouring compounds
Aldehydes
| Ketones
83
What functional groups do aldehydes and ketones contain
Carbonyl
84
What is the difference between an aldehyde and a ketone
Aldehyde- there is always a hydrogen bonded to the carbonyl group
Ketone- two carbons bonded to the carbonyl group
85
What is the simplest member of the aldehyde series
Methanal
86
What is the simplest member of the ketone series
Propanone
87
How do you identify the name of an aldehyde and a ketone
Aldehyde- "-al"
| Ketone- "-one"
88
Is the number of the carbon which the carbonyl group is bonded to necessary in the name of an aldehyde
No, it is always at the end of the carbon chain
89
Can aldehyde and ketones be oxidised
Aldehydes yes
| Ketones resist mild oxidation
90
What can aldehyde oxidise to
Carboxylic acids
91
What happens to the aldehyde molecules when it is oxidised
An oxygen is inserted into the C-H bond attached to the carbonyl group
92
Why can't a ketone be oxidised
It doesn't have a hydrogen atom attached to the carbonyl group
93
Name 4 oxidising agents
Copper(II) oxide
Acidified potassium dichromate
Fehlings solution
Tollens solution
94
What is the colour change when copper(II) oxide is reduced
Black to brown
95
What is the colour change when acidified potassium dichromate is reduced
Orange to Blue/green
96
What is the colour change when Fehlings solution is reduced
Blue to brick red
97
What is the colour change when Tollens solution is reduced
Clear/colourless to silver mirror
98
What happens to the oxygen to hydrogen ratio during oxidation
Increase
99
What happens when food is exposed to the air
It oxidises and spoils
100
What functional group do the alcohols contain
Hydroxyl group
101
How do you recognises an alcohol from its name
The "-ol" ending
102
When an alcohol contains two hydroxyl groups what is the name given to it
Diol
103
What is the polarity of alcohols and why
Polar due to the presence of the hydroxyl group which allows hydrogen bonds to form
104
What are the three structural types of alcohols
Primary
Secondary
Tertiary
105
Describe primary alcohols
Hydroxyl group attached to a carbon atom with at least two hydrogen atoms
106
Describe a secondary alcohol
Hydroxyl group bonded to a carbon atom attached to one hydrogen atom
107
Describe a tertiary alcohol
Hydroxyl group is attached to a carbon with no hydrogen atoms attached
108
Describe the steps in the oxidisation of primary alcohols
Primary alcohols
Aldehydes
Carboxylic acids
109
Deacons the steps in the oxidisation of a secondary alcohol
Secondary alcohol
| Ketone
110
Describe the steps of the oxidisation of a tertiary alcohol
Resists mild oxidation
111
What does an increase in the oxygen to hydrogen ratio mean
The addition of oxygen or the removal of hydrogen
112
What happens in the first stage of oxidising a primary alcohol
Two hydrogen atoms are removed to produce an aldehyde
113
What happens in the second stage of oxidising a primary alcohol
Oxygen is added to the aldehyde
114
What happens when a secondary alcohol is oxidised
Two hydrogen atoms are removed to produce a ketone
115
What are needed for the oxidisation of an alcohol to occur
Oxidising agent
116
What functional groups do carboxylic acids contain
Carboxyl group
117
What two functional groups are carboxyl groups made of
A carbonyl group and a hydroxyl group
118
How can you recognise a carboxylic acid from its name
The "-oic acid" ending
119
What are isomers
Compounds with the same molecular formula but different structural formula
120
What other group of compounds are isomers to carboxylic acids
Esters
121
What is the reverse reaction to oxidising
Reducing
122
What are the steps of reduction of a carboxylic acid
Carboxylic acid
Aldehyde
Primary alcohol
123
What are the steps of the reduction of a ketone
Ketone
| Secondary alcohol
124
What is the effect of reduction in the oxygen to hydrogen ratio
Decrease
125
What type of reaction is it when a carboxylic acids reacts with
1) some metals
2) alkalis
3) carbonates
4) metal oxides
1) redox
2) neutralisation
3) neutralisation
4) neutralisation
126
What type of reaction do foods undergo when they react with the air and spoil
Oxidation
127
How can you prevent oxidation
Antioxidants
128
What is an antioxidant
A compound easily oxidised itself that it protects other compounds from being oxidised
129
Ascorbic acid is an example of what
An antioxidant
130
What is produced when one mole of fat or oil is hydrolysed
One mole of glycerol
| Three miles of fatty acids
131
What catalyst is used in the manufacture of soaps
Sodium (or potassium) hydroxide solution
132
What does the alkali catalyst do in the production of soaps
Catalysed the hydrolysis reaction and then neutralises the fatty acids to form the sodium (or potassium) salts
133
What chemicals are needed to produce a soap
Fats and oils
| Sodium hydroxide catalyst
134
What is the structure of a soap
Hydrophobic tail
| Hydrophilic head
135
What is the polarity of the head of a soap
Ionic as it is soluble in water
136
What is the polarity of the tail of the soap
Non polar as it is insoluble in water
137
Where do the heads and tails go of a soap when washing grease off a plate in water
Hydrophobic tails bury themselves in the grease while the hydrophilic heads remain in the water
138
How do soaps prevent grease droplets from joining together
The head of each soap is negatively charged and so the grease droplets repel each other
139
Are detergents synthetic or naturally occurring
Synthetic
140
Detergents are usually derived from crude oil
| True or false
True
141
Describe the structure of a detergent molecule
Long non-polar hydrocarbon tail (hydrophobic) and an ionic head (hydrophilic)
142
What is the advantage of detergents over soaps
When soaps react with hard water they form insoluble salts known as scum whereas with detergents no scum is formed
143
What is hard water
Water which contains either calcium ions and/or magnesium ions
144
What is an emulsion
A mixture of liquids where one liquid is dispersed throughout the other
Not a solution
145
What is used to prevent emulsions
Emulsifiers
146
Describe the structure of an emulsifier
Hydrophobic tails and hydrophilic heads
147
What are emulsifiers made of
Glycerides
| Esters of glycerol and fatty acids
148
Describe what is meant by a
1) monoglyceride
2) diglyceride
3) triglyceride
1) contains one fatty acid linked to a glycerol
2) contains two fatty acids linked to a glycerol
3) contains three fatty acids linked to a glycerol
149
Are emulsifiers
a) monoglycerides
b) diglycerides
c) triglycerides
d) any of the above
e) just monoglycerides and diglycerides
e)
150
What makes the heads of molecules hydrophilic
The hydroxyl group
151
How do emulsifiers work
Prevent the oil and water from separating
152
Why can triglycerides not act as emulsifiers
They do not contain any hydroxyl groups which allow them to dissolve in water
153
What are essential oils
Concentrated extracts of volatile compounds from plants that have pleasant aromas and are insoluble in water
154
How are essential oils extracted from plants
Steam distillation
155
Where are essential oils used
```
Perfumes
Cosmetics
Foods
Cleaning products
Solvents
Alternative medicines
```
156
What are the most important and abundant constituent of essential oils
Terpenes
157
What are oxygen containing terpenes called
Terpenoids
158
The skeletons of terpenes molecules usually contain ...... atoms in multiples of......
Carbon
| Five
159
What is the building block of terpenes
Isoprene
160
What is the molecular formula for isoprene
C5H8
161
What is the systematic name for isoprene
2-methlybuta-1,3-diene
162
What is the one of the simplest terpenes
Myrcene
163
What are the key components of essential oils
Terpenes and terpenoids
164
What are edible oils
Found in plants and are made of triglycerides
165
What are mineral oils
Derived from crude oil and contain long chain alkanes
166
What is ultraviolet light
Makes up part of sunlight and is a high energy form of radiation
167
What can UV light do to skin
Break chemical bonds in molecules leading to reactions which destroy skin tissue
168
What do sun block products contain
Zinc oxide
| Titanium dioxide
169
What does zinc oxide and titanium dioxide do in relation to sunlight
Reflect UV radiation and do not allow any UV radiation through the skin
170
What does sun screen contain
P-aminobenzoic acid
171
What does p-aminobenzoic acid do in relation to sunlight
Absorbs some of the UV radiation so that less reaches the skin
172
What is a benefit of absorbing small amounts of UV radiation
Generation Vitamin D
173
What are free radicals
Atoms or groups of atoms with an unpaired electron and is highly reactive
174
What are the three steps in the free radical chain reaction
Initiation
Propagation
Termination
175
What happens in the initiation stage of a free radical chain reaction
UV light provides an energy source to break bonds of molecules and so the atoms now have unpaired electrons and are extremely unstable and highly reactive
Free radicals are generated
176
What happens in the propagation stage of a free radical chain reaction
Free radicals attack other molecules creating more free radicals
177
What does the propagation stage of a free radical chain reaction do in the chain reaction
Sustain it
178
What happens in the termination stage of a free radical chain reaction
The number of free radicals build up and collisions between them occur and stable molecules are produced
And thus the reaction ends
179
UV radiation interacts with compounds in the skin and fats are produced
True or false
False
| Free radicals
180
What are free radical scavengers
They reacts with free radicals to from stable molecules and prevent chain reactions
181
What are two common free radical scavengers
Vitamin C and E
