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Higher Chemistry Unit 2 > Part 2 > Flashcards

Part 2 Flashcards

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1
Q

How is oxidation and reduction defined?

A

As increasing the O:H ratio and reduction is defined as decreasing the O:H ratio.

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2
Q

Do the oxidation and reduction definitions always apply

A

No, they only apply in carbon chemistry.

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3
Q

Look at and read the oxidation equation and example on top of page 20

A

k

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4
Q

What is the functional group of the alkanals?

A

-CHO

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5
Q

How are alkanals named?

A

By replacing the ‘ol’ of the alkanol with -al.

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6
Q

Draw out the first 3 members of the alkanals on page 20.

A

ok

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7
Q

What is the C=O group on alkanals called?

A

The carbonyl group

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8
Q

Any compound containing the CHO group is called an…

A

aldehyde.

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9
Q

The alkanals, which are derivatives of _____, are a sub-group of _____.

A

alkanes, aldehydes

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10
Q

How are alkanals made?

A

By oxidising primary alkanols.

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11
Q

What is the main industrial use of alkanals? Give an example.

A

Making thermosetting plastics, e.g. phenol/methanal resins.

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12
Q

Methanal (formadehyde) is also used in the preservation of…

A

bodies and dead animals.

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13
Q

What is the functional group of the alkanones?

A

C=O, the carbonyl group. This group must be with a chain.

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14
Q

How do you name an alkanone?

A

By replacing the ‘ol’ of the alkanol with -one.

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15
Q

Write out the first 3 alkanone on page 20.

A

Ok

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16
Q

What are alkanones are subset of?

A

The more general ketones.

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17
Q

How are alkanones made?

A

By oxidising secondary alkanols

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18
Q

What are the uses of ketones?

A

Mainly as solvents for varnishes and plastics, e.g. propanone is the solvent in nail varnish remover.

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19
Q

Why do aldehydes and ketones behave similarly in many reactions?

A

Because they both contain the carbonyl group C=O.

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20
Q

Aldehydes can be oxidised to _____ whereas ketones cannot.

A

carboxylic acids

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21
Q

Name the three oxidising agents.

A
  • Benedict’s or Fehling’s solution
  • Tollen’s reagent
  • Acidified potassium dichromate solution
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22
Q

What is the observation and reason when using the oxidising agent Benedict’s or Fehling’s solution?

A

Blue solution -> orange-red precipitate

Cu2+ irons reduced to Cu2O, i.e. copper (1) oxide

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23
Q

What is the observation and reason when using oxidising agent Tollen’s reagent (AgNo3(aq) + NH3(aq)

A

A ‘silver mirror’ is formed.

Ag+ ions reduced to Ag atoms.

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24
Q

What is the observation and reason when using oxidising agent acidified potassium dichromate solution?

A

Orange solution -> blue-green solution

Cr2O7 2- reduced to Cr3+

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25
Q

Why do glucose, fructose etc give positive tests with Benedicts solution?

A

They contain the aldehyde group -CHO.

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26
Q

Compounds whose molecules contain the carboxyl functional group (-COOH) are generally called…

A

carboxylic acids (aka alkanoic acids)

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27
Q

Draw out the carboxlyic/alkanoic acids on page 21

A

ok

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28
Q

The carboxyl group in alkanoic acids is able to___

A

release a hydrogen ion when in water and this gives rise to acid reactions

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29
Q

What is the equation for carboxylic acids releasing a hydrogen?

A

CH3COOH -> (reversible arrow) CH3COO- + H+

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30
Q

The negative ion in the carboxylic acid releasing a hydrogen equation is called…

A

The ethanoate ion

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31
Q

Generally, the ion produced from alkanoic acids when they ionise is called an…

A

alkanoate ion

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32
Q

look at the equations on page 22

A

ok

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33
Q

Ethanoic acid, a carboxylic acid also known as acetic acid, when in a fairly dilute solution is used as…

A

vinegar

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34
Q

What is ethanoic acid used as a feedstock for?

A

The producation of ethenyl ethanoate (an unsaturated ester) and this can be used to make a polymer poly (ethenyl ethanoate) which is used a lot in paints.

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35
Q

Soaps are made from ____ ____ which have fairly long ____, e.g. stearic acid can be easily reacted to make sodium stearate, a common compound found in soap.

A

carboxylic acids, chains

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36
Q

Molecules with two carboxyl groups on their molecules (dicarboxlyic acids) can be used to make…

A

the polymers Terrylene and nylone-6,6

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37
Q

revise the PPA on ester formation

A

okay

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38
Q

What are esters?

A

Esters are compounds formed by a condensation reaction between alcohols and carboxylic acids.

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39
Q

How do you name esters?

A

The first bit comes from the alkanol (alcohol) and becomes yl. The second comes from the alkanoic acid (carboxylic acid) and changes to oate.

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40
Q

What is the main reaction of esters?

A

Hydrolysis (the reverse of condensation)

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41
Q

How are esters formed?

A

As the result of the loss of water molecule between an alkanol and alkanoic acid.

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42
Q

How do you reform an ester into the original acid and alkanol?

A

By reacting the ester with a water molecule.

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43
Q

The formation and hydrolysis of an ester is an example of a ______ reaction

A

reversible

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44
Q

Concentrated sulpjhuric acid is a powerful ____ agent

A

dehydrating. This means it absorbs water.

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45
Q

If the alkanoic acid/alkanol mixture is heated with a few drops of concentrated sulphuric acid then…

A

it is possible to get a good quantity of ester.

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46
Q

How can the ester be separated from the rest of the reaction?

A

By pouring it into a solution of sodium carbonate - this neutralises the acid and the oily ester layer forms on top.

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47
Q

page 24. write out the stuff about reversing the formation of an ester from the top until properties and uses of esters.

A

k

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48
Q

What are the uses for small esters?

A

Solvents in adhesives, inks and paints, e.g. pentyl ethanoate is used in nail varnish

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49
Q

What are bigger esters used for?

A
  • flavourings
  • perfumes
  • natural fruit flavours
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50
Q

What is the odour/flavour of the ester pentyl ethanoate?

A

Banana

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51
Q

What is the odour/flavour of the ester octyl ethanoate?

A

Orange

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52
Q

What is the odour/flavour of the ester methyl butanoate?

A

Pineapple

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53
Q

What is the odour/flavour of the ester 3-methylbutyl butanoate?

A

Apple

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54
Q

What are the reasons for rarely getting the total quantity of product that we calculate from the chemical equation?

A
  • There may be reactant left unconverted to product
  • Some reactant may be converted into a by-product
  • The isolation of the product may be difficult
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55
Q

What is the equation for calculating percentage yield?

A

actual quantity obtained divided by theoretical quantity from equation x 100

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56
Q

have a look at the example on page 25 of percentage yield

A

ok

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57
Q

What is polythene used for?

A

Plastic basins, polystyrene foams, nylon and other synthetic fibres and the special plastic needed for CDs and microchip circuit boards.

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58
Q

What are the two main types if reaction that allow molecules to be polymerised?

A

Addition and condensation.

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59
Q

How can ethene be obtained?

A

By cracking of the ethane from the gas fraction from crude oil, OR by cracking the naptha fraction.

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60
Q

Draw out the cracking process of ethane and naptha on page 26.

A

k

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61
Q

p.26 draw diagram of cracking propane to produce propene and hydrogen

A

k

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62
Q

Draw out the polymerisation reaction of propene on p.26

A

k

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63
Q

What is phenylethene (styrene) important in the making of?

A

poly(phenylethene) or polystyrene.

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64
Q

p.26 draw reaction of phenylethene to poly(phenylethene)

A

k

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65
Q

All of the addition polymerisations involve using the addition reaction of the…

A

c=c double bond thousands of times.

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66
Q

What is a second feature of addition reactions?

A

The small molecules (monomers) were of the same type.

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67
Q

p.27 draw out examples of repeating unit and monomer.

A

k

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68
Q

How is it possible to make thousands of ester links and form long chains?

A

If you use a small molecule with two acids groups and another small molecule with two hydroxyl groups.

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69
Q

The condensation polymer (terylene) is a ____ polymer (a fibre)

A

linear

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70
Q

What is the polymer tetrylene used for?

A

The fibres of it can be spun together to give a strong, flexible product used in clothing. It can also be used in making photographic films and recording tapes.

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71
Q

Where are resins from?

A

They can be made from polyesters.

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72
Q

If there are C=C double bonds (it is unsaturated) the fibres can ______ ______ giving a 3D network.

A

cross link

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73
Q

These resins, unlike the polyester fibres, are…

A

thermosetting

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74
Q

What are resins made from polymers used for?

A
  • in conjunction with glass fibre to form glass reinforced plastic (GRP) which is light, inexpensive and hard-wearing. It is used in boats, car bodies and in building.
75
Q

To stop a polymer from continuing, add…

A

a substance with only one functional group

76
Q

What are molecules with an amine (or amino) functional group (the Amines) an example of?

A

Condensation polymerisation.

77
Q

What are the first 3 members of the amines?

A
  • aminomethane (methylamine)
  • aminoethane (ethylamine)
  • 1-aminopropane (propylamine)
78
Q

draw out the first 3 amines on p.28

A

k

79
Q

How can amines be thought of?

A

Amines can be thought of as arising from ammonia by replacing a hydrogen with an alkyl group.

80
Q

How is the similarity between amines and ammonia shown?

A

By their reaction with copper (11) sulphate solution. Both amines and ammonia give a deep blue solution.

81
Q

draw out the diagram at the bottom of page 28.

A

k

82
Q

The link formed in polyamide formation is what?

A

Amide link.

83
Q

What is the best known polyamide?

A

Nylon.

84
Q

Polyamides are classed are _____ polymers.

A

Condensation.

85
Q

Nylon is an extremely important _____ polymer with great strength for its weight.

A

engineering

86
Q

How is nylon so strong for such a light material?

A

Due to strong hydrogen bonding between the chains and along the length of the polymer chains

87
Q

When we are dealing with condensation polymers, the monomers must both have…

A

two functional groups.

88
Q

In condensation polymers, the ‘repeating unit’ must indicate…

A

the structures of both the monomers used.

89
Q

draw out the repeating unit for nylon 6,6 on p.29

A

k

90
Q

Methanal and phenol react together….

A

to form bakelite, a thermosetting plastic.

91
Q

The reaction to make bakelite is another example of _____ polymerisation

A

condensation

92
Q

The chains in bakelite cross link to give a

A

3D covalent network. This is a very strong strcuture which does not soften on heating (a thermosetting palstic).

93
Q

methanal and urea also react by a condensation polymerisation to produce…

A

urea methanal resin, another themosetting plastic.

94
Q

Where is urea methanal and bakelite found?

A

Pot handles, light fittings, formica work tops and other situations with where thermoplastics would soften or melt.

95
Q

What can poly(ethyne) be used for?

A

Making conducting membranes for high performance loudspeakers.

96
Q

How do conducting polymers work?

A

If ethyne is used to make an addition polymer, we still have a chain which is very unsaturated. Look at the diagram on p.30. The structure is able to allowed delocalised electrons to pass along it.

97
Q

What can poly(vinyl carbazole), a conducting polymer, do?

A

It has the property of photoconductivity - it can conduct better when light is shone on it.

98
Q

What is poly(vinyl carbazole) used in?

A

Photocopying machine.

99
Q

Look at the poly(vinyl carbazole) structure on p.30. It is an addition poylmer.

A

ok

100
Q

What is the bulletproof pollymer?

A

Kevlar

101
Q

Look at the diagram for kevlar on p30

A

k

102
Q

How is Kevlar special?

A

Te chains of alternating aromatic rings align themselves in a flat formation which makes it possible to hydrogen bond in a very regular and closely packed formation as shown.

103
Q

Why does Kevlar have great strength?

A

Due to extensive bonding.

104
Q

What is Kevlar used to make?

A

Very strong ropes and cords for car tyres. It is much stronger than steel yet considerably lighter.

105
Q

What can Kevlar be used to make when stiffened?

A

Wings on aircraft, bulletproof vests, safety jackets for fencers and body protectors for motocyclists and horse riders.

106
Q

Why are most polymers bad for the environment?

A

They are all very stable and do not break down.

107
Q

What are degradeable polymers?

A

Polymers which do break down and are less likely to cause environmental damage.

108
Q

If poly(ethene) is made in such a way that carbonyl groups can be introducted into the chain, we have…

A

a polymer which can break down on exposure to light.

109
Q

What allows the absorption of strong sunlight in poly(ethene)?

A

The presence of the carbonyl groups.

110
Q

How is poly(ethene) biodegradable?

A

The energy trapped by the carbonyl groups is used to break carbon-carbon bonds near the group and this eventually breaks the molecules into smaller chunks which can biodegrade.

111
Q

What is poly(ethene) used for?

A

As can rings around six pack drinks. It;s going to be used more in carrier bags, packaging material and as protective films around young plants.

112
Q

How is poly(ethenyl ethanoate) made into poly(ethenol)

A

It can be reacted with methanol in a reaction called ester exchange in which the ester groups along the chain are replaced as can be seen in the reaction scheme (p32)

113
Q

The poly(ethenol) is water soluble if…

A

the number of OH groups along the chain is controlled.

114
Q

look at the table on p.32

A

k

115
Q

Why is pure poly(ethenol) insoluble in water?

A

Because the OH groups are involved in a deal of internal hydrogen bonding so water is unable to interfere with structure. If however, the internal hydrogen bonding is broken up by having the ester groups at regular sites along the chain then water is able to break into the structure and dissolve it.

116
Q

What is poly(ethenol) used for?

A

To make laundy bags for hospitals (the laundy is put in to the washing machines enclosed in the bags and the bag quickly dissolves away, exposing the laundry to the washing liquid. It is also used for soluble stitches in surgery and to make protective coatings for cards which can be hosed off.

117
Q

What is biopol?

A

A biodegradeable polymer.

118
Q

What is the structure of biopol?

A

The polymerisation of 3-hudroxybutanoic acid to make poly (3-hydroxybutanoate) or PHB for short.

119
Q

How is biopol made commercially?

A

By using bacteria in a fermenting mixture.

120
Q

Draw out the basic monomer of biopol

A

p.33

121
Q

What is the problem which prevents biopol being used in medical fields for surgical stitches and for holding broken bones while they healed?

A

High production costs.

122
Q

Give examples of oils from vegetable origin.

A
  • Soybean oil
  • Palm oil
  • Olive oil
  • Castor oil
  • Linseed oil
123
Q

Give examples of oils from animal origin

A
  • whale oil

- cod liver oil

124
Q

Give examples of fats

A
  • Pork fat (lard)
  • Mutton fat
  • Beef fat
125
Q

What is the obvious difference between fats and oils?

A

Fats are solid at room temperature.

126
Q

Melting points are lower for oils or fats?

A

oils

127
Q

What is the main chemical difference between fats and oils?

A

Oils have a higher level of unsaturation - they contain many more C=C double bonds.

128
Q

How can we prove that oils are more unsaturated than fats?

A

By shaking oils with bromine water - the brown colour disappears readily. If fats, dissolved in a suitable saturated solvent, are tested with bromine water the brown colour remains.

129
Q

The shape of both oil and fat molecules is roughly that of a…

A

tuning fork.

130
Q

What does the tuning fork shape mean?

A

The absence of a double bond (in fats) allows the molecules to be more reguarly tuning fork shaped and then the molecules can fit into one another. If a double bond is present (oils0 then the molecules zigzag, chains become distorted and cannot fit into one another.

131
Q

Molecules which can pack closely together due to their regular structure (i.e. fats) have stronger…

A

Van der Waals forces and therefore higher melting points.

132
Q

WHy do marine animals that live in cold oceans often have oils?

A

Because fats would be solid and could not be transported round the body.

133
Q

How do you harden oils into fats?

A

By reacting the double bonds with hydrogen. This is an addition reaction and changes unsaturated compounds into saturated ones.

134
Q

How are margarines made?

A

By partial hydrogenation of oils using a nickel catalyst.

135
Q

What can produce margarines with different properties?

A

The degree of hydrogenation along with different forms of refinement and bleding.

136
Q

What various ingredients are added to margarines to improve taste, appearance, saleability and health?

A
  • Vitamin A and D (mainly obtained from oils and fats and which people obtained from butter and must be added to butter substitutes)
  • colouring materials
  • emulsifiers (water/oil emulsion and to keep the emulsion stable it is necessary to add emulsifying agents such as lecithin)
  • Flavouring agents (to enhance butter flavour)
137
Q

What is the main dietary function of fats and oils?

A

To provide energy. They release twice as much energy as carbs.

138
Q

Fats and oils provide the body with some vitamins such as…

A

A, D, E and K as these vitamins are soluble in fats/oils.

139
Q

Fats and oils are actually special forms of ____ where the alcohol, glyceral (propane-1,2,3-triol) has three hydroxyl groups.

A

Ester

140
Q

Glycerol is termed a _____ ____ because it has three hydroxyl groups.

A

trihydric alcohol.

141
Q

Draw glycerol

A

p.35

142
Q

Each of the hydroxyl groups forms an ____ _____ with a long chain carboxylic acid - there are called fatty acids.

A

Ester linkage.

143
Q

in fatty acids, it is in the acid chain that we find the absence or presence of the double bond - if there is a double bond the acid is called…

A

an alkenoic acid.

144
Q

Give examples of fatty acids

A
  • Palmitic acid
  • Stearic acid
  • Oleic acid
  • Linoleic
145
Q

Fatty acids are ______ or ______ straight chain carboxylic acids with even numbers of C atoms ranging from _____ to _____ but mainly ___ to ____.

A

saturated or unsaturated. Ranging from c4 to C24 but mainly C16 to C18

146
Q

p.36 draw out the typical fat molecule.

A

k

147
Q

The fat or oil molecule is called a ….

A

triglyceride

148
Q

When a fat or oil is formed, the glycerol molecule can…

A

react with 3 different fatty acid molecules.

149
Q

What is any particular fat, such as beef fat, made of?

A

A mixture of different triglycerides. So no fat or oil is a pure triglyceride.

150
Q

Is it possible to break up fat and oil molecules into the glycerol (the alcohol part) and the fatty acids? If so, how?

A

By hydrolysis. This can be done by treatment with superheated steam. In the lab, this hydrolysis is normally done using aqueous acid or alkali.

151
Q

What is a very important example of the hydrolysis of fats and oils?

A

The production of soaps.

152
Q

What are soaps made from?

A

Fats and oils by hydrolysing them using solutions of sodium hydroxide or potassium hydroxide. The fatty acid is formed as the sodium or potassium salts. There salts are ‘salted out’ of the reaction mixture by adding a great excess of sodium chloride and the soap can then be filtered off

153
Q

What are soaps and detergents?

A

Emulsifying reagents.

154
Q

Why can most of dirt on skin, clothes and dishes not be washed away with water?

A

Because it tends to be trapped in oils and greases.

155
Q

How are soaps and detergents’ sttructures good for washing?

A

Sodium or potassium salts of long chain fatty acids have two separate parts in terms of their bonding types - a long hydrocarbon chain which is non polar and an ionic head. Non polar molecules are very insoluble in water but soluble in non polar solvents such as oil. Ionic compounds (esp. alkali metals) are generally soluble in water but not in non polar solvents. Soap molecules have two sets of solubility properties in different parts of their structure which makes them good emulsifying agents.

156
Q

look at the diagram on p.37

A

lol k

157
Q

Are proteins big molecules?

A

YES, and they are made up from smaller molecules called amino acids - i.e. they are natural polymers.

158
Q

The smaller molecules in proteins (amino acids) (monomers) contain two functional groups. What are they?

A

the amine group NH2 and the carboxyl group COOH.

159
Q

Natural amino acids must have…

A

the two functional groups (NH2 and COOH) bonded to the same carbon atom

160
Q

What are the simplest two a-amino acids?

A

Glycine and alanine.

161
Q

look at p38

A

yah

162
Q

Because amino acids have two functional groups on their molecules, they can therefore react as ____ and as ____

A

acids and bases

163
Q

To react as acids, what is added to the amino acid?

A

NaOH

164
Q

And to react as a base, what is added to the amino acid?

A

HCL

165
Q

How are proteins made?

A

By the condensation of amino acid molecules to give a long sting like molecule. Proteins are therefore considered condensation polymers of amino acids.

166
Q

Skipped all the stuff on p39 on amino acids

A

kl

167
Q

Why do proteins have a very large molecular mass?

A

Due to their being made from several thousand amino acid molecules.

168
Q

How can proteins be broken down to amino acids?

A

By hydrolysis like all condensation polymers.

169
Q

How can proteins be broken down to amino acids IN A LAB?

A

By ‘refluxing’ the protein with fairly concentrated hydrochloric acid. Look at the diagram on p.39. In the stomach, enzymes more efficiently hydrolyse the proteins into the amino acids

170
Q

How can the amino acids produced by the breakdown of proteins be identified?

A

By using the technique of chromatography.

171
Q

unlike the pigments in ink, amino acids are ___ and ____ so the spots on paper must be developed in chromatography using a special solution.

A

colourless and invisible

172
Q

How can it be shown that proteins are nitrogen containing compounds>

A

By heating the protein with a strong alkali. Soda lime is usually used for this.

173
Q

Describe the test to show that proteins are nitrogen containing compounds.

A

If the protein is ground up with soda lime and gently heated in a test tube alkaline gases are given off - this can be shown using damp pH paper which turns blue. This only confirms the substance contains nitrogen.

174
Q

Nature only uses ___ different structures of amino acids

A

26

175
Q

Protein molecules normally consist of several ____ amino acids ____ together.

A

thousand, condensed

176
Q

The absence of even one of the essential amino acids can lead to…

A

serious dietary defiencencies.

177
Q

In many Asian and African countries, the people live on a highly restricted vegetarian diet and the availability of all the essential amino acids is limited —

A

protein deficiency diseases such as kwashiorkor affect many people as a result.

178
Q

Fibrous proteins are the ones which form the…

A

structural materials in animal tissues e.g. skin, muscle, hair, nails.

179
Q

Globular proteins tend to have.

A

spiral chains folded and twisted round into more compact units and generally the ones which are involved in the chemistry of metabolic regulation. e.g. enzymes, hormones (e.g. insulin) and haemoglobin for the transport of oxygen within the bloodstream are globular proteins.

180
Q

draw out the structures of both proteins on p41

A

k

181
Q

All enzymes are totally protein in their structure but some need another part to function. What is this part called?

A

A co-enzyme.

182
Q

Enzymes are said to be specific. What does this mean?

A

That each enzyme only catalyses one reaction

183
Q

Some chemical processes involve a sequence of reactions each stage of which requires….

A

a different enzyme.

Higher Chemistry Unit 2 (6 decks)

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