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Alevel Chemistry OCR A > Module 4: Section 1- Basic Concepts And Hydrocarbons > Flashcards

Module 4: Section 1- Basic Concepts And Hydrocarbons Flashcards

1
Q

Organic basics
What are the 6 types of formula

A

General
Empirical
Structural
Displayed
Skeletal
Molecular

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2
Q

Organic basics
What is a general formula

A

Algebraic formula can describe any member of a family of compounds

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3
Q

Organic basics
What does an empirical formula show

A

Simplest whole number ratio of atoms of each element is a compound

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4
Q

What is a molecular formula

A

Actual number of atoms in a molecule

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5
Q

Organic basics
What is the displayed formula

A

Shows how atoms are arranged and all the bonds between them

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6
Q

Organic basics
What is the skeletal formula

A

Shows bonds of carbon skeleton only with any functional groups
Carbon and hydrogen atoms aren’t show
Each point represents a carbon

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7
Q

Organic basics
Define functional group

A

Feature of a molecule which defines its characteristic reactions

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8
Q

Organic basics
Define homologous series

A

Group of organic molecules with the same functional group and same general formula where each successive member increased by CH2

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9
Q

Organic basics
Prefix or suffix for alkanes

A

-ane

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10
Q

Organic basics
Prefix or suffix for branched alkanes

A

Alkyl-(-yl)

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11
Q

Organic basics
Prefix or suffix for alkenes

A

-ene

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12
Q

Organic basics
Prefix or suffix for haloalkanes

A

Chloro-/bromo-/iodo-

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13
Q

Organic basics
Prefix or suffix for alcohols

A

-ol/hydroxy-

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14
Q

Organic basics
Prefix or suffix for aldehydes

A

-al

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15
Q

Organic basics
Prefix or suffix for ketones

A

-one

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16
Q

Organic basics
Prefix or suffix for cycloalkanes

A

Cyclo-…-ane

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17
Q

Organic basics
Prefix or suffix for carboxylic acids

A

-oic acid

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18
Q

Organic basics
Prefix or suffix for esters

A

Alkyl- … -anoate

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19
Q

Organic basics
What’s doe unsaturated mean

A

Prescience of double bonds

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20
Q

Organic basics
What does saturated mean

A

All single bonds

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21
Q

Organic basics
What does aliphatic mean

A

anything with a chain of carbons

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22
Q

Organic basics
What does alicyclic mean

A

Cyclic of carbon

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23
Q

Organic basics
What does aromatic mean

A

Delocalised pi system (mostly in y13)

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24
Q

Organic basics
What is an alkyl group

A

Forage,nt of a molecule with general formula Cn H2n+1

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25
Q

Organic basics
What is nomenclature

A

Naming organic compounds

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26
Q

Organic basics
What is IUPAC

A

Naming system for organic compound which was invented as an international language for chemistry and can be sued for any organic compound a systematic name using the rules

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27
Q

Organic basics
Number of carbon - name stem (1-4

A

1 is meth-
2 is eth-
3 is prop-
4 is but-

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28
Q

Organic basics
Number of carbons -stem (5-10

A

5 is pent-
6 is hex-
7 is hept-
8 is oct-
9 is non-
10 is dec-

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29
Q

Organic basics
What gives the prefix or suffix

A

Main functional group usually tell you what homologous series the molecule is is and so the prefix or suffix

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30
Q

Organic basics
IUPAC rule for numbers

A

Number the longest carbon chain so that the main functional group has the lowest possible number

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31
Q

Organic basics
What are side chains or less important functional groups added as

A

Prefixes in alphabetical order after the number of carbon atom each it’d attached to

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32
Q

Organic basics
What do you do if there’s more than one side chain or functional group

A

Use di-(2), tri- (3), or tetra- (4) before that part of the name

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33
Q

Isomers
What are isomers

A

Two molecules are isomers if they have the same molecular formula but atoms are arranged differently

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34
Q

Isomers
What are the two types of isomers

A

Structural isomers and stereoisomers

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35
Q

Isomers
What are structural isomers

A

Compounds with the same molecular formulas but different structural formulae

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36
Q

Isomers
What’s are the three types of structural isomers

A

Chain isomers
Positional isomers
Functional group isomers

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37
Q

Isomers
What are chain isomers

A

When the carbon skeleton is arranged differently eg straight chain or branched in different ways

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38
Q

Isomers
Effect of chain isomers on properties

A

Isomers have similar chemical properties by their physical properties such as boiling point will be different

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39
Q

Isomers
Why do chain isomers have different physical properties

A

Because of the change in the shape of the molecule

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40
Q

Isomers
What are positional isomers

A

Skeleton and the functional group could be the same only with the functional group attached to a different carbon atom

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41
Q

Isomers
Effect of positional isomers on characteristics

A

Different physical properties and the chemical properties might be different too

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42
Q

Isomers
What are futnional group isomers

A

Same atoms can be arranged into different functional groups

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43
Q

Isomers
Effect of functional group isomers on characteristics

A

Different physical and chemical properties

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44
Q

Isomers
What is a functional group isomer of aldehyde

A

Ketone

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45
Q

Isomers
What is the functional group isomer of carboxylic acid

A

Ester

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46
Q

Isomers
What is the functional group isomer of alkenes

A

Cycloalkanes

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47
Q

Isomers
What is the functional group isomer of ketones

A

Aldehydes

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48
Q

Isomers
What is the functional group isomer of esters

A

Carboxylic acids

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49
Q

Isomers
What is the functional group isomer of cycloalkanes

A

Alkenes

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50
Q

Alkanes
What is the general formula of alkanes

A

CnH2n+2

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51
Q

Alkanes
What are alkanes

A

Saturated hydrocarbons

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52
Q

Alkanes
What shape is around each carbon and bond angle

A

Tetrahedral
109.5

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53
Q

Alkanes
What are the bonds called in alkanes

A

Covalent specifically Sigma bonds

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54
Q

Alkanes
What are sigma bonds

A

Overlap of orbitals directly between the bonding atoms

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55
Q

Alkanes
What are the standard states of alkanes

A

CH4 to C4H10 aregases
C5H12 to C17H36 are liquids
C18H38 above are solids

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56
Q

Alkanes
What are between the molecules

A

London forces which hold them together

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57
Q

Alkanes
Why happens to the boiling point as the carbon chain gets longer

A

Increases

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58
Q

Alkanes
Why does the boiling point increase as the boiling point gets longer

A

Longer chain, stronger London forces because of more surface contact so more electrons to interrupt, takes more energy to overcome the imf

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59
Q

Alkanes
Why does a branched chain alkane have lower boiling point than a straight chain isomer

A

Can’t pack closely together and they have smaller molecular surface areas so the London forces are reduced

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60
Q

Alkanes
What happens if you burn alkanes with oxygen and what type of reaction is it

A

Produce carbon dioxide and water
Combustion reaction

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61
Q

Alkanes
What’s the equation for complete combustion of propane

A

C3H8 (g) + 5 O2 (g) —> 3 CO2 (g) + 4 H2O (g)

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62
Q

Alkanes
What state does combustion ave to happen between

A

Gases

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63
Q

Alkanes
What has to be done to liquid alkanes before combustion

A

Have to be vaporised first

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64
Q

Alkanes
Why doe smaller alkanes burn easier

A

They turn into gases more easily (more volatile)

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65
Q

Alkanes
Why do larger alkanes releases more energy per mole

A

Have more bonds to break

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66
Q

Alkanes
Why do alkanes make excellent fuels

A

Because they release so much energy when they burn

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67
Q

Alkanes
What is a common question for alkanes

A

Using volumes to work out combustion equations

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68
Q

Alkanes
How can you workout what hydrocarbon is combusting

A

All gases at the same temperature and pressure have the same molar volume, which means you can use the ratio of the volumes of gases reacting to calculate molar mass and workout the hydrocarbon

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69
Q

Alkanes
What does incomplete combustion produce

A

Carbon monoxide and water

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70
Q

Alkanes
Equation for burning methane with not enough oxygen

A

2 CH4 (g) + 3 O2 (g) —> 2 CO (g) + 4 H2O (g)

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71
Q

Alkanes
What is the problem with incomplete production

A

It produced carbon monoxide which is poisonous

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72
Q

Alkanes
Health impacts of carbon monoxide

A

The oxygen in your bloodstream is carried around by haemoglobin.
Carbon monoxide is better at binding to haemoglobin than oxygen is, so it
binds to the haemoglobin in your bloodstream before the oxygen can.
This means that less oxygen can be carried around your body, leading to oxygen deprivation. At very high concentrations, carbon monoxide can be fatal.

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73
Q

Alkanes
What are free radicals

A

Particles that have unpaired electrons

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74
Q

Alkanes
What do alkanes react with

A

Free radicals

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75
Q

Alkanes
What is bond fission

A

Breaking a covalent bonds

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76
Q

Alkanes
What are the two types of bond fission

A

Homolytic and heterolytic

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77
Q

Alkane
What happens in heterolytic fission

A

The bond breaks unevenly with one of the bonded atoms receiving both electrons from the bonded pair

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78
Q

Alkanes
What’s formed from heterolytic fission

A

Two different substances, a positively charged cation (X+) and a negatively charged anion (Y-)

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79
Q

Alkanes
Mechanism of heterolytic fission

A

X—:—Y -> X+ + Y-
(Curly arrow from electrons in bond to the Y)

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80
Q

Alkanes
What does a curly arrow show

A

The movement of an electron pair

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81
Q

Alkanes
What happens in homolytic fission

A

Bond breaks evenly and each binding atom receives one electron from the bonded pair

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82
Q

Alkanes
What’s formed from homolytic fission

A

Two electrically uncharged radicals

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83
Q

Alkanes
What are radicals

A

Particles that have an unpaired electron

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84
Q

Alkanes
How are radicals shown in mechanisms

A

By a big dot next to the molecular formula to represent the unpaired electron

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85
Q

Alkanes
Mechanism for homolytic fission

A

X—:—Y -> X• + Y•

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86
Q

Alkanes
Why are radicals very reactive

A

Because of the unpaired electron

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87
Q

Alkanes
What’s formed when halogens react with alkanes

A

Haloalkanes

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88
Q

Alkanes
What type of reaction os halogens reacting with alkane

A

Photochemical reactions

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89
Q

Alkanes
How are photochemical reactions started

A

By light

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90
Q

Alkanes
What is needed in photochemical reaction for halkoalkanes to be formed

A

Ultraviolet light

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91
Q

Alkanes
What is substituted in the reaction to form a haloalkane and what is it called

A

Hydrogen atom is substituted by chlorine or bromine

92
Q

Alkanes
What dos the reaction of chlorine and methane form

A

Chloromethane and hydrochloric acid

93
Q

Alkanes
Equation for chlorine and Methane

A

CH4 + Cl2 —uv-> CH3Cl + HCl

94
Q

Alkanes
Whatare the three stages of the reaction mechanism for free radical substitution

A

Initiation reactions
Propagation reactions
Termination reactions

95
Q

Alkanes
What two halogens are needed to know

A

Chlorine and bromine (interchangeable

96
Q

Alkanes
What happens in the intimation reactions

A

Sunlight provides enough energy to break the Cl-Cl bond (photodissociation)
Cl2 -uv-> 2 Cl•
This is through homolytic fission and two highly reactive free radicals are formed Cl• because of its unpaired electron

97
Q

Alkanes
What happens in the propagation reactions of free radical substitutions

A

Cl• attacks a methane molecule: Cl• + CH4 —> •CH3 +HCl
The new methyl free radical •CH3 can attack another Cl2 molecule: •CH3 + Cl2 —> CH3Cl + Cl•
The new Cl• can attack another CH4 molecules and so on until all the Cl2 or CH4 molecules are wiped out

98
Q

Alkanes
What happens in termination of free radical substitution

A

If two few radicals join together a stable molecule is formed so there are heaps of possible termination reactions such as
Cl• + •CH3 —> CH3Cl
•CH3 + •CH3 —> C2H6

99
Q

Alkanes
What are the two problem of free radical substitution in organic synthesis

A

-Further substitution produces a mixture of products
-substitution can occur at different positions in the carbon chain producing isomers

100
Q

Basics of reactions
What’s an addition reaction

A

When two reactants joint together to form one product

101
Q

Basics of reactions
What is a substitution reaction

A

Atom or group of atoms is replaced by A different atom or group of atoms

102
Q

Alkanes
What is thermal decomposition and what is it know as in alkanes

A

Using heat to break up a substance
Cracking

103
Q

Basics of reactions
What is produced in thermal decomposition (cracking)

A

Long chains —> shorter chain alkanes + alkenes

104
Q

Properties of Alkenes
What are alkenes

A

Unsaturated hydrocarbons

105
Q

Properties of Alkenes
What is unique about alkenes

A

Contain at least one carbon carbon double bond in the structure

106
Q

Properties of Alkenes
What us the general formula of aliphatic alkenes

107
Q

Properties of Alkenes
What can be true of alkenes

A

They can be branched contain more than one double bond or be cyclic
General formula only applied to branched and aliphatic alkenes

108
Q

Properties of Alkenes
What is the bonding on the carbon atom of the double bond

A

Three of the four electrons are used in three sigma bonds, and one of the four electrons in a pi bond

109
Q

Properties of Alkenes
How does the double bond structure

A

First sigma bond between the two carbons formed then one electron left which is in a p orbital. A pi bond is formed by the sideways overlap of the 2 p orbitals one from each carbon atom in the double bond

110
Q

Properties of Alkenes
Why is there a high pi electron density in the double bond

A

Electrons concentrated around the line joining the nuclei of the bonded atoms

111
Q

Properties of Alkenes
What is true of pi bond but not sigma bonds

A

Sigma bonds are freely rotating but pi bonds lock the two carbon atoms in position and restrict rotation around the double bond

112
Q

Properties of Alkenes
What is the shape around each of the carbon atoms in the double bond

A

Trigonal planar

113
Q

Properties of Alkenes
What are the bond angles around the a carbon atom in the double bond

A

120 degrees

114
Q

Properties of Alkenes
Why is the shape around the carbon atom in a double bond Trigonal planar

A

Because there are three regions of electron density around each of the carbon atoms
The three regions repel each other as far as possible resulting in the 120 degree bond angle
All atoms are on the same plane

115
Q

Properties of alkenes
How can you test for alkenes

A

Using bromine water

116
Q

Properties of alkenes
Positive test for alkenes using bromine water

A

Causes bromine water to chnage from orange-brown colour to colourless

117
Q

Properties of alkenes
Why does bromine water go colourless in alkenes

A

Bromine forms bonds to the carbon atoms removing the double carbon bond causing it to be saturated

118
Q

Alkenes, stereoisomerism
What are stereoisomers

A

Have the same structural formula but different arrangement of atoms in space

119
Q

Alkenes, stereoisomerism
What are the two types of stereosisomerism

A

E/Z isomerism and optical isomerism

120
Q

Alkenes, stereoisomerism
When can E/Z isomerism only occur

A

In compounds with a C=C double bond and different group attached to each carbon in the double bond

121
Q

Alkenes, stereoisomerism
When can optical isomerism occur

A

In a wider range of compound including alkanes with not functional group

122
Q

Alkenes, stereoisomerism
Why does stereoisomerism aris around double bonds

A

Because rotation about the double bond is restricted and the groups attached to each carbon atoms are therefore fixed relative to each other

123
Q

Alkenes, stereoisomerism
What two conditions does a molecule have to satisfy to have E/Z isomerisms

A

-a C=C double bond
-different groups attached to each carbon atom of the double bond

124
Q

Alkenes, stereoisomerism
What is true of the E isomers

A

High priority groups are apart (one above one below) of the C=C double bond

125
Q

Alkenes, stereoisomerism
What is true of Z isomers

A

High priority groups are on the same side of the C=C double bond

126
Q

Alkenes, stereoisomerism
What is Cis-trains isomerism

A

a special case of E/Z isomerism where molecules must fit the basic two conditions of E/Z isomers but also one of the attached groups on each carbon of the double bond must be the same

127
Q

Alkenes, stereoisomerism
What is the cis isomer

A

When groups are on the same side of the molecule

128
Q

Alkenes, stereoisomerism
What is the trans molecules

A

When the groups are on opposite sides

129
Q

Alkenes, stereoisomerism
What is true when there is a hydrogen on each of the double bonded carbon atoms in cis-trans isomerism

A

The cis isomer is the Z isomer
The trans isomer is the E isomer

130
Q

Alkenes, stereoisomerism
What are the Cahn-Ingold-Prelog rules

A

Naming system to give priority to groups in molecules that display E/Z isomers

131
Q

Alkenes, stereoisomerism
How do the CIP rules give priority’s to groups

A

Atoms or groups with higher Mr have priority

132
Q

Alkenes, stereoisomerism
Using the CIP rules to decide on the isomer

A

On either carbon of the double bond identify the highest priority group and the location of it in comparison to the other carbon atom then use either E/Z or cis-trans isomerism

133
Q

Reactions of Alkenes
Why are alkenes more reactive then alkanes

A

Because of the presence of the pi bond

134
Q

Reactions of Alkenes

Why does the pi bond mean alkenes undergo addition reactions relatively easily

A

Double bond made of a sigma and pi bond so pi electron density concentrated above and below plane of the sigma bond and the electrons are more exposed than the electrons in the sigma bond. Pi bond breaks easily so undergo addition reactions relatively easily

135
Q

Reactions of Alkenes
What is the bond enthalpy of a pi bond and what are the ramifications of this

A

Relatively low bond enthalpy so makes them relatively reactive

136
Q

Reactions of Alkenes
What happens in addition reaction

A

Involved addition of a small molecule across the double bond causing the pi bond to break and new bonds to form

137
Q

Reactions of Alkenes
Example of addditon reactions for alkenes

A

Hydrogen in prescient of nickel catalyst
Halogen
Hydrogen halides
Steam in prescience of an acid catalyst

138
Q

Reactions of Alkenes
What is hydrogenation of alkenes

A

When mixed with hydrogen and passed over a nickel catalyst an addition reaction takes place to form an alkane

139
Q

Reactions of Alkenes
What is the definition of hydrogenation

A

When hydrogen is passed across a double bond and is added

140
Q

Reactions of Alkenes
Example fo hydrogenation of propene

A

CH3CHCH2 + H2 —> CH3CH2CH£

141
Q

Reactions of Alkenes
What is halogenation of alkenes

A

Addition reaction with halogens chlorine or bromine

142
Q

Reactions of Alkenes
Reaction for the bromination of propene

A

CH3CHCH2 + Br2 —> CH3CHBrCH2Br

143
Q

Reactions of Alkenes
What is catalytic hydrogenation used to manufacture

A

Margarine and unsaturated vegetable oils

144
Q

Reactions of Alkenes
What is the test for unsaturation

A

Bromine water added dropwise and turns colourless indicating presence of a C=C double bond

145
Q

Reactions of Alkenes
What is the addition reaction of alkenes with hydrogen halides

A

Alkenes react with gaseous halides at room temperature to form haloalkanes

146
Q

Reactions of Alkenes
What happens if the alkene is a gas and hydrogen a gas

A

Two gases are mixed

147
Q

Reactions of Alkenes
What happens if alkene if a liquid with hydrogen halide

A

Hydrogen halide bubbled throughout

148
Q

Reactions of Alkenes
What happens if alkenes react with concentrated hydrochloric or hydrobromic avid

A

They are solutions of hydrogen halides in water so form haloalkanes

149
Q

Reactions of Alkenes
What could happen if an unsymmetrical alkene reacts with an unsymmetrical compound

A

Two products could be made

150
Q

Reactions of Alkenes
What are hydration reactions of alkenes and what are the conditions

A

Alcohols formed when alkenes react with stream H2O (g) in presence of a pohosphoric acid catalyst

151
Q

Reactions of Alkenes
Where does steam add in a hydration reaction

A

Across the double bond

152
Q

Reactions of Alkenes
What is the hydration reaction used widely in

A

Industry to produce ethanol from ethene

153
Q

Reactions of Alkenes
What does the hydration reaction often result in

A

A mixture of alcohols

154
Q

Reactions of Alkenes
What’s the reaction between propene and steam in the presence of a phosphoric acid catalyst

A

Propene + H2O (g) —> propan-1-ol
—> propan-2-ol

155
Q

Electrophilic addition in alkenes
What is electrophilic addition

A

Mechanisms that alkenes usually take part in addition reactions to form saturate compounds

156
Q

Electrophilic addition in alkenes
What does the double bond in an alkene represent

A

A region of high electron density because of the prescence of the pi-electrons

157
Q

Electrophilic addition in alkenes
What does the high electron density of the pi-electrons

A

Attracts electrophiles

158
Q

Electrophilic addition in alkenes
What are electrophiles defined as

A

Electron pair acceptor

159
Q

Electrophilic addition in alkenes
What are electrophiles actually

A

Atom or group of atoms that is attracted to an electron rich centre and accepts and electron pair

160
Q

Electrophilic addition in alkenes
What happens in an electrophilic addition reaction

A

Alkene double bond is an area of high electron density so it more susceptible to attack by electrophiles
C=C bond breaks forming a single c-c bond and two new bonds from each of the carbon atom

161
Q

Electrophilic addition in alkenes
For hydrogen halides why is it polar

A

Hydrogen and halogen atoms have different electronegativity so halogen has delta negative charge and H has delta positive charge

162
Q

Electrophilic addition in alkenes
Why can hydrogen halide act as electrpphile

A

Delta positive hydrogen attracted to C=C double bond with high electron density

163
Q

Electrophilic addition in alkenes
What happens in an electrophilic addition of a hydrogen Halide

A

H atom acts as electrophilic by accepting pair of electrons from the C=C bond in the Alkene
This results in formation of a carbocation intermediate as the hydrogen forms a bond width a carbon which reacts with the halide ion
Halide ion the attracted to positive carbocation forming a bond

164
Q

Electrophilic addition in alkenes
For the mechanism of electrophilic addition where does the first curly arrow move from and to

A

From the C=C double bond to the delta positive atom of the thing which is being added

165
Q

Electrophilic addition in alkenes
Where does the second curly arrow go from and two in the mechanism

A

The bond between the molecule adding and the delta negative

166
Q

Electrophilic addition in alkenes
What is important to add to the molecule being added on a mechanism

A

Dipoles (delta + and delta -)

167
Q

Electrophilic addition in alkenes
What is the intermediate

A

An alkane with the first bond formed and a + on the carbon
There will also be a negative ion

168
Q

Electrophilic addition in alkenes
What is a carbocation

A

Positive ion with a positive charge on the carbon

169
Q

Electrophilic addition in alkenes
Where is the curly arrow and on the intermediate mechanism

A

From the negative charge on the negative ion to the positive on the carbocation

170
Q

Electrophilic addition in alkenes
What is the last part of a mechanism

171
Q

Electrophilic addition in alkenes
What is key for the curly arrow on any mechanism

A

Be double headed to show movement of a pair of electrons
Start from lone pair of electrons or area of high electron density eg directly from C=C bond
Move towards an electrophilic or positive charge of a carbocation

172
Q

Electrophilic addition in alkenes
For halogens whats the dipole

A

Induced dipole caused by repulsion of the halogens e;extrinsic by the high electron density C=C bond on the Alkene

173
Q

Electrophilic addition in alkenes markownikoff
What is a carbocation

A

Positively charged carbon atom with only three covalent bonds instead of four

174
Q

Electrophilic addition in alkenes markownikoff
What are the three types of carbocation

A

Primary secondary and tertiary

175
Q

Electrophilic addition in alkenes markownikoff
What’s a primary carbocation

A

Only one other carbon bonded to carbon ion

176
Q

Electrophilic addition in alkenes markownikoff
What’s a secondary carbocation

A

Two carbons around the carbon ion

177
Q

Electrophilic addition in alkenes markownikoff
What’s a tertiary carbocation

A

Three carbons around the carbon ion

178
Q

Electrophilic addition in alkenes markownikoff
What does markownikoffs rule allow us to predict

A

Products of electrophilic addition

179
Q

Electrophilic addition in alkenes markownikoff
How many different products can be produced from asymmetric electrophiles and what are they ca;led

A

2 (major and minor)

180
Q

Electrophilic addition in alkenes markownikoff
What’s the major product

A

More likely to be made,most common

181
Q

Electrophilic addition in alkenes markownikoff
What’s the minor product

A

Least likely to be made, less common

182
Q

Electrophilic addition in alkenes markownikoff
What allows us to predict the minor or major product

A

Depending on the stability of the carbocation

183
Q

Electrophilic addition in alkenes markownikoff
What happens to the stability of the carbocation as more carbons are added around the con

A

Increases stability
Tertiary most stable
Primary least stable

184
Q

Electrophilic addition in alkenes markownikoff
What does a carbocation being more stable mean

A

Less likely to return to original structure
More likely to pick up more electronegative

185
Q

Electrophilic addition in alkenes markownikoff
What is the major product

A

When more electronegative atom bonded to most stable carbocation

186
Q

Polymers from alkenes
What is addition polymerisation

A

Many monomers containing at least one C=C double bond form long chain polymers as the only product

187
Q

Polymers from alkenes
What is a polymer

A

Long chain molecule that is made up of many repeating units

188
Q

Polymers from alkenes
What are monomers

A

Small reactive molecules that react together to form polymers

189
Q

Polymers from alkenes
What is the general equation

A

Written for any addition reaction and uses the symbol n to balance it either displayed or general formulas

190
Q

Polymers from alkenes
Example of general equation for ethene

A

nC2H4 —> -[-C2H4-]- n

191
Q

Polymers from alkenes
What are repeat units

A

Specific arrangement of atoms in the polymer molecule that repeats over and over

192
Q

Polymers from alkenes
In the gerenal equation what is the repeat unit always shown in

A

Square brackets

193
Q

Polymers from alkenes
Difference between monomer and repeat unit

A

Repeat unit always drawn in square brackets with a singe carbon bind
Monomer has double C=C bond
Both have symbol n

194
Q

Waste polymers and alternatives
Why are polymers used

A

Provide readily available cheap alternative to metal glass paper and cardboard materials

195
Q

Waste polymers and alternatives
Impact of low reactivity of many polymers

A

Ideal for certain uses such as packaging food but at Sam time creates problems with their disposal as lots are non biodegradable which creates environmental problems such as killing marine animals

196
Q

Waste polymers and alternatives
What are the methods of polymer disposal

A

Landfill
Recycling
Combustion for energy
Feedstock recycling bio plastics

197
Q

Waste polymers and alternatives
Why is using landfill not ideal

A

Bad for environment

198
Q

Waste polymers and alternatives
Why can polymers be recycled

A

Reduced the amount of waste into landfill
Can have recycling point at newer landfill sites

199
Q

Waste polymers and alternatives
How does recycling polymers reduce the use of finite resources

A

Lots of polymer made from products of cracking crude oil

200
Q

Waste polymers and alternatives
What’s bad about recycling polymers

A

Time consuming as have to be sorted into different categories

201
Q

Waste polymers and alternatives
What happens after sorting to recycle polymers

A

Chopped washed dried and melting then cats into pellets ready for use

202
Q

Waste polymers and alternatives
Why can certain polymers cause problems when recycling

A

Due to their chemical composition such as PVC contains lost of toxic chlorine

203
Q

Waste polymers and alternatives
Why is combustion used to recycle polymers

A

When incinerates release large amount of energy which can boil water and turn turbines inside a power station

204
Q

Waste polymers and alternatives
Negative of combustion to dispose of polymers

A

Causes environmental pollution as carbon within polymer can be released as CO2 contributing to global warming
Other toxic waste products like Cl2 can be released

205
Q

Waste polymers and alternatives
What is feedstock recycling

A

Where waste polymers are broken down be chemical and thermal processes into monomers gases and oils which are then used as the raw materials in the production of new polymers and organic chemicals

206
Q

Waste polymers and alternatives
What’s the major benefit of feedstock recycling

A

Compared to other methods it works with unsorted and unwashed polymers

207
Q

Waste polymers and alternatives
What are bioplastics

A

Polymers that are made from plant starch plant oils and plant proteins

208
Q

Waste polymers and alternatives
Why are bioplastics good

A

Provide a renewable and sustainable alternative to the current polymers which are bases on finite resources such as crude oil

209
Q

Waste polymers and alternatives
What are biodegradable polymers

A

Can be broke down over time by microorganisms

210
Q

Waste polymers and alternatives
Why are biodegradable polymers good

A

Degrade amend leave no visible or toxic trace

211
Q

Waste polymers and alternatives
What are photodegradable polymers

A

Contain bonds which are weakened by light to start degradation
Many are oil based

212
Q

Waste polymers and alternatives
Benefit of photo degradable polymers

A

Can be recycled better

213
Q

Polymers
What polymers might you need to name

A

Poly(ethene)
Poly(chloroethene)
Polypropylene
Phenylethene / styrene
Tetrafluorothene

214
Q

Polymers
How’s poly(ethene) made

A

Heating a large number of etehne molecules at a high pressure

215
Q

Polymers
Monomer of poly(ethene)

216
Q

Polymers
Uses of poly(ethene)

A

Most commonly used eg supermarket bags and shampoo bottles

217
Q

Polymers
What is poly(chloroethene) known as

218
Q

Polymers
What are the two ways poly(chloroethene) can be made into

A

Rigid or flexible

219
Q

Polymers
Monomer of poly(chloroethene)

A

Chloroethene

220
Q

Polymers
What is poly(chloroethene) used in

A

Pipes bottles and flooring

221
Q

Polymers
Monomer of polypropylene

222
Q

Polymers
What is polypropylene used in

A

Packing material and foood cups

223
Q

Polymers
Why is polypropylene used in food cups

A

Has thermal insulating properties

224
Q

Polymers
Monomer of tetrafluoroethene

A

Tetrafluoroethene

225
Q

Polymers
What is poly(tetrafluoroethene) used for

A

Coating for nonstick pans and cable insulation

Alevel Chemistry OCR A (18 decks)

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