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a level chemistry > module 4 section 1 - basic concepts and hydrocarbons > Flashcards

module 4 section 1 - basic concepts and hydrocarbons Flashcards

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1
Q

what is a homologous series ? (1)

A

family of compounds with similar chemical properties

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2
Q

name the first 4 alkanes (4)

A
  • methane
  • ethane
  • propane
  • butane
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3
Q

Draw the functional group of an alkene

A
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4
Q

Draw the functional group of alcohol

A
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5
Q

Draw the functional groups of a halo alkane

A
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6
Q

Draw the functional group of an aldehyde

A
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7
Q

Draw the functional group of a ketone

A
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8
Q

Draw the functional group of a carboxylic acid

A
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9
Q

What is the suffix of an alkene?

A
  • ene
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10
Q

What is the suffix of an alcohol?

A

-ol

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11
Q

What is the suffix of an aldehyde? 

A

-al

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12
Q

What is the suffix of a ketone? 

A

-one

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13
Q

What is the suffix of a carboxylic acid? 

A

-oic acid

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14
Q

What is an organic compound ? (1)

A

All contain element carbon

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15
Q

Give 3 reasons why carbon forms a large number of compounds (3)

A
  • each carbon atom can form 4 cov bonds
  • single double or triple
  • carbon atoms can bind to other carbon atoms to form long chains
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16
Q

What is a saturated hydrocarbon ? (1)

A

-single bonds only

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17
Q

What is an unsaturated hydrocarbons ? (1)

A

One or more C=C

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18
Q

What is a homologous series ? (1)

A

Family of compounds w similar chemical properties

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19
Q

When is an organic molecules functional group responsible for ? (1)

A
  • responsible for mlcls chemical properties
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20
Q

What 3 ways can hydrocarbons be classified as ? (3)

A
  • aliphatic
  • alycylic
  • aromatic
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21
Q

What is an aliphatic hydrocarbon ?(3)

A
  • carbon atoms joined to each other
  • in unbranched or branched chains
  • or non aromatic rings
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22
Q

What is an alycylic hydrocarbon (3)

A

-carbon atoms joined to each other
- in ring structures
- with or without branches

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23
Q

What is an aromatic hydrocarbon ? (2)

A
  • some or all carbon atoms
  • Found in a benzene ring
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24
Q

What are the 3 homologous series of aliphatic hydrocarbons (3)

A
  • alkanes
  • alkenes
  • alkynes
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25
Q

What are alkanes ? (1)

A
  • contain C-C bonds
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26
Q

What are alkenes ? (1)

A

Contain at least 1 C=C

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27
Q

What are alkynes ? (1)

A

Contain at least 1 triple carbon - to - carbon bond

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28
Q

What type of hydrocarbon is shown here ?

A

Aliphatic

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29
Q

What type of hydrocarbon is shown here ?

A

Alicylic

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30
Q

What type of hydrocarbon is shown here ?

A

Aromatic

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31
Q

What prefix is used when naming cycloalkanes ? (1)

A

Cyclo

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32
Q

State the functional group in this molecule

A

Chloroalkane

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33
Q

State the functional group in this molecule

A

Ketone

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34
Q

State the functional group in this molecule

A

Alcohol

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35
Q

State the functional group in this molecule

A

Bromoalkane

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36
Q

what are the 2 types of bond fission ? (2)

A
  • homolytic fission
  • heterolytic fission
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37
Q

what do bond fissions do ? (1)

A

break cov bonds

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38
Q

what happens during a homolytic fission (3)

A
  • each of bonded atoms takes one e- from shared pair from bond
  • each atom now has single unpaired e-
  • forming a radical
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39
Q

what is a radical ? (2)

A
  • atom or groups of atoms
  • with an unpaired e-
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40
Q

what happens during a hetrolytic fission (3)

A
  • one of bonded atoms takes both of e- from bond
  • atom that takes both becomes a -ive ion
  • atom that doesnt take becomes +ive ion
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41
Q

what is a reaction mechanism ? (1)

A

how a reaction takes place

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42
Q

what do curly arrows in reaction mechanisms show ? (2)

A
  • movement of electrons
  • when bonds are being broken or made
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43
Q

what does a full headed arow show ? (2)

A
  • movement of a pair of e-
  • when bonds are being broken or made
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44
Q

what does a half headed arrow show ? (2)

A
  • movement of single unpaired e-
  • in mechanisms involving radicals
  • when bonds are being broken or made
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45
Q

what are the 3 types of reaction ? (3)

A
  • addition
  • substitution
  • elimination
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46
Q

what is an addition reaction (2)

A
  • 2 reactions join
  • to form 1 product
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47
Q

what is a substitution reaction (2)

A
  • atom or group of atoms replaced
  • by diff atoms or group of atoms
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48
Q

what is an elimination reaction ? (2)

A
  • removal of a small mlcl from a larger one
  • 1 reactant, 2 products
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49
Q

Draw the homolytic fission of the carbon carbon bond in methane

A
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50
Q

Draw the hetrolytic fission of the carbon - chlorine bind in Chloromethane

A
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51
Q

Use a curly arrow to show the movement of a pair of electrons in the hetrolytic fission of the carbon - chlorine bind in chloromethane

A
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52
Q

Draw the reaction mechanism for the homolytic fission of a carbon - hydrogen bond in Methane

A
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53
Q

What type of reaction is shown here ?

A

Addition

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54
Q

What type of reaction is shown here

A

Substitution

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55
Q

What type of reaction is shown here

A

Elimination

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56
Q

Show the homolytic fission of a chlorine - chlorine bind in a chlorine atom

A
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57
Q

describe the bonding in alkanes (2)

A
  • saturated hydrocarbons- single bonds
  • bonds called sigma bonds
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58
Q

what is a sigma bond ? (3)

A
  • single cov bond
  • formed by direct overlap of orbitals
  • between bonding atoms
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59
Q

describe the shape of alkanes (5)

A
  • 4 bond regions
  • 0 lone pairs
  • tetrahedral
  • 109.5 degrees
  • bonded pairs repel eachother equally
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60
Q

what is the strongest intermolecular force found in an alkane ?

A

IDDI ( london forces)

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61
Q

describe the polarity of alkanes (1)

A

non polar

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62
Q

describe the trends in BP’s of alkanes (5)

A
  • as chain length increases BP increases
  • as points of contact increase
  • and no. e- increase
  • so greater london forces (IDDI)
  • so more energy needed to overcome
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63
Q

compare the BP’s of branched alkanes and their straight chain counterpoints (4)

A
  • branched have lower BP
  • as fewer surface points of contact
  • so weaker IDDI
  • so less energy needed to overcome
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64
Q

define homologous series (2)

A
  • a family/series/groups of mlcls w same functional group
  • each successive member differs by CH2
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65
Q

write the general formula of cycloalkanes (1)

A

CnH2n+2

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66
Q

describe the reactivity of alkanes (2)

A
  • unreactive because C-C and C-H sigma bonds are strong
  • bonds arev unreactive
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67
Q

what 2 reactions can be undergone by alkanes ? (2)

A
  • combustion
  • free radical substitution
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68
Q

what are the products of complete combustion of an alkane ?

A

CO2 and H20

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69
Q

what are the 2 possible product combinations on an incomplete conbustion of an alkane (2)

A
  • CO and H2O
  • C and H2O
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70
Q

write the balanced equation for the complete combustion of butane including state symbols

A

CH3CH2CH2CH3 (g) + 6.5O2 (g) = 4CO2 (g) + 5H2O (l)

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71
Q

in what order of elements should you balance in a complete and incomplete combustion ?

A

C H O

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72
Q

write the balances symbol equation for the incomplete combustion of butan to produce carbon monoxide

A

CH3CH2CH2CH3 (g) + 4.5O2 (g) = 4CO (g) + 5H2O (l)

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73
Q

write the balances symbol equation for the incomplete combustion of butan to produce carbon monoxide

A

CH3CH2CH2CH3 (g) + 2.5O2 (g) = 4C (g) + 5H2O (l)

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74
Q

state one issue caused by the production of carbon in incomplete combustion

A

global dimming

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75
Q

what is the state symbole of most alkanes ?

A

(g)

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76
Q

what is the state symbol of heptane ?

A

(l)

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77
Q

what is an isomer ? (2)

A
  • same Mr
  • diff atom arrangement
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78
Q

what are the 2 types of isomers ? (2)

A
  • structural isomers
  • stereoisomers
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79
Q

what are structural isomers ? (2)

A
  • same Mr
  • diff structural formula
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80
Q

what are the 3 types of structural isomers ? (3)

A
  • chain isomers
  • positional isomers
  • functional group isomers
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81
Q

what are chain isomers ? (1)

A
  • carbon skeleton arranged differently
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82
Q

what are positional isomers ? (3)

A
  • same skeleton
  • same functional group
  • functional group attached to diff carbon atom
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83
Q

what are functional group isomers ? (1)

A
  • same stoms arranged into diff functional groups
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84
Q

explain the properties of chain isomers (3)

A
  • similar chem properties
  • diff physical properties eg BP
  • because of change in shape of mlcl
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85
Q

explain the properties of positional isomers (2)

A
  • diff physical properties
  • diff chem properties
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86
Q

explain the properties of functional group isomers (2)

A
  • very diff chem properties
  • very diff physical properties
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87
Q

what type of isomers are shown here (2)

A
  • structural
  • chain isomers
88
Q

what type of isomers are shown here ? (2)

A
  • structural
  • positional isomers
89
Q

what type of isomers are shown here ? (2)

A
  • structural
  • functional group isomers
90
Q

what is the functional group in 2-methylpentan-1-ol and why is it necessary to state its position on the carbon chain ? (3)

A
  • OH = hydroxyl
  • could be attached to any of 5 carbons
  • position of OH affects its chemistry
91
Q

what are stereoisomers ? (2)

A
  • same structural formula
  • diff arrangement in space
92
Q

what are the 4 types of stereoisomers ?

A
  • cis
  • trans
  • E
  • Z
93
Q

when can stereoisomers occur ? (2)

A
  • when 2 double bonded C atoms
  • each have 2 diff atoms or groups attached to them
94
Q

what is a Z - isomer ?

A
  • groups or atoms with highest atomic number
  • on Zame Zide
95
Q

what is an E isomer ? (1)

A
  • groups or atoms with highest atomic number
  • on opp sides
96
Q

name a saturated structural isomer of hex-2-ene

A

cyclohexane

97
Q

place Cl, H, Br and F in order of decreasing priority as indicated by CIP rules (4)

A

Br>Cl>F>H

98
Q

what must be done to determine which group has a higher priority if the ATOMS DIRECTLY bonded to the carbon atom are the same (1)

A

look at next atom in group

99
Q

how is priority determined in E/Z isomers according to CIP rules ? (1)

A

larger atomic number = higher priority

100
Q

when can stereoisomers be called Cis or Trans isomers ?

A

if carbon atoms have at least 1 group in common

101
Q

explain why alkenes can have E/Z isomers but alkanes cannot (2)

A
  • E/Z isomers occur because atoms cant rotate about C=C double bonds
  • alkenes contain C=C double bonds but alkanes dont
102
Q

what causes alkenes to form stereoisomers ? (1)

A
  • restricted rotation around C=C double bond
103
Q

what are the saturated structural isomers of straight chain alkenes ? (1)

A

cycloalkanes

104
Q

what is a nucleophile ? (2)

A
  • atom or group
  • donates pair of e- to form new cov bond
105
Q

what is an electrophile ? (2)

A
  • atom of group
  • accepts pair of e- to form new cov bond
106
Q

what are nucleophiles attracted to ? (1)

A

electron deficient centre or atom

107
Q

what are electrophiles attracted to ? (1)

A

electron rich centre or atom

108
Q

what type of reactions do electrophiles undergo ?

A

addition

109
Q

what type of reaction do necleophiles undergo ?

A

substitution

110
Q

what is the mechanism of a substitution reaction undergone by a nucleophile called ? (1)

A

nucleophilic substitution

111
Q

give 4 examples of nucleophiles (4)

A
  • Br-
  • OH-
  • H20
  • NH3
112
Q

give 3 examples of electrophiles (3)

A
  • Br2
  • HBr
  • NO2+
113
Q

State the nucleophile shows in this nucleophilic attack

A

OH-

114
Q

Name the electrophile in this addition reaction

A

Br2

115
Q

State the nucleophile in this nucleophilic attack

A

OH-

116
Q

Draw the E and Z isomers of but-2-ene writing their specific names

A
117
Q

Draw the E and Z isomers for 2-Chloro-but-2-ene including their specific names

A
118
Q

Name this stereoisomer

A

Trans-1-Bromopropene

119
Q

Describe the reactions of alkanes with halogens in the dark or at room temperature (1)

A

No reaction

120
Q

When is an alkane able to react with a halogen? (1)

A

Presence of uv or sunlight

121
Q

State the products of the reaction between an alkane and a halogen in the presence of sunlight (2)

A
  • Haloalkane
  • hydrogen halide
122
Q

Explain now halogenation of an alkane happens (2)

A

• via homolytic bond fission
. Forming Free radicals

123
Q

Write an equation for the reaction of methane with bromine and state the main product formed (2)

A

CH4(g) + Br2 (l) = CH3Br(g) HBr(g)

  • Bromomethane
124
Q

What are the 3 main steps in the mechanism of a free radical substitution (3)

A
  • Initiation
  • propagation
  • termination
125
Q

Show the initiation mechanism using bromine

A

Br2 =2 br•

126
Q

Show the propagation steps using methane and bromine

A

Br• +CH4 =HBr + •Ch3

•Ch3 + Br2 = CH3Br + Br•

127
Q

Write the termination reactions continuing the reactions of methane with bromine (3)

A

Br• + Br• = Br2

•CH3 + •CH3 = C2H6

•CH3 + Br• = CH3Br

128
Q

Why are alkanes able to react with halogens in the presence of sunlight (2)

A
  • Uv radiation in sunlight
  • provides initial energy for reaction to take place
129
Q

what type of reactions happen to alkenes ? (1)

A

electrophilic addition reactions

130
Q

what happens when an alkene undergoes an electrophilic addition reaction ? (2)

A
  • double bond opens up
  • atoms added to carbon atoms
131
Q

what do electrophiles include ? (2)

A
  • positively charged ions
  • polar molecules
132
Q

why do electrophilic addition reactions happen to alkenes ? (2)

A
  • double bond has many electrons
  • easily attacked by electrophiles
133
Q

name the electrophilic addition reactions undergone by alkenes (4)

A
  • adding hydrogen
  • halogenation (addition of halogens)
  • hydration
  • addition of hydrogen halides
134
Q

what is the product when an alkene undergoes hydrogen addition ? (1)

A

alkane

135
Q

describe the conditions required for an alkene to undergo hydrogen addition (2)

A
  • nickel catalyst
  • 150 degrees celcius
136
Q

what is the product formed when an alkene undergoes halogenation ? (1)

A
  • dihaloalkane
137
Q

what is the product formed when alkenes undergo hydration ? (1)

A

alcohol

138
Q

what type of reacion is the alkene hydration ? (1)

A

reversible reactioons

139
Q

what conditions are reaquired for alkene hydration to take place ? (3)

A
  • high temp around 300 degrees celcius
  • high pressure around 60-70 atm
  • solid phosphoric (V) acid catalyst
140
Q

describe how alkene hydration takes place (2)

A
  • steam added
  • across double bond
141
Q

explain how halogenation is used to test for unsaturation (2)

A
  • shake an alkene w orange bromine water
  • = colourless
142
Q

Using displayed formula show the reaction which occurs when ethene undergoes hydrogen addition and name the product formed

A

Ethane

143
Q

Using structural formula show the reaction undergone when ethene undergoes hydrogen addition

A
144
Q

Using displayed formula show the halogenation reaction between ethene and chlorine and name the product formed

A
145
Q

Using displayed formula show the halogenation reaction between propane and bromine and name the product formed

A
146
Q

Using structural formula write the general equation for the halogenation reaction of alkenes

A
147
Q

Using ethene and chlorine as an example show the mechanism for the halogenation reaction between them and name the product formed

A
148
Q

Using structural formula show the hydration reaction undergone by ethene and name the product formed

A

Ethanol

149
Q

Using ethene as an example show the mechanism for hydration reactions and name the product formed

A

Ethanol

150
Q

Using displayed formula show the addition of hydrogen halide reaction which takes place when hydrogen bromide reacts with Ethene and name the product formed

A
151
Q

Show the reaction mechanism for the reaction between ethene and hydrogen bromide

A
152
Q

Show the reaction mechanism for the reaction between cyclohexane and hydrogen bromide

A
153
Q

How many products are formed when a hydrogen halide is added to an unsymmetrical alkene ?

A

2

154
Q

What is an alkyl group ? (1)

A

A functional group

155
Q

What are the three types of carbocations ? (3)

A
  • primary carbocation
  • secondary carbocation
  • tertiary carbocation
156
Q

How many alkyl groups does a primary carbocation have ?

A

1

157
Q

How many alkyl groups is a tertiary carbocation attached to ?

A

3

158
Q

How many alkyl groups is a secondary carbocation attached to ?

A

2

159
Q

Which carbocation is the most stable ? (1)

A

Tertiary carbocation

160
Q

Which carbocation is the least stable ? (1)

A

Primary carbocation

161
Q

Why is a carbocation which has more alkyl groups more stable that a carbocation which has less alkyl groups ? (2)

A
  • alkyl groups feed electrons towards + charge
  • so carbocation more likely to form
162
Q

Using the reaction between hydrogen bromide and propene determine which product is the major product and which product is the minor product

A
163
Q

How do you know which product is a major product and which product is a minor product when a hydrogen halide is added to an unsymmetrical alkene ? (2)

A
  • major product - more stable carbocation
  • minor product + least stable carbocation
164
Q

Which product is more likely to form when adding a hydrogen halide to an unsymmetrical alkene ? (1)

A

Major product

165
Q

What is Markownikoff’s rule ? (3)

A
  • major product of addition of a hydrogen halide to an unsymmetrical alkene
  • is the one where hydrogen adds to the carbon
  • with most hydrogens already attached
166
Q

What is the product formed when hydrogen halides are added to alkenes ? (1)

A

Haloalkanes

167
Q

How are hydrogen halides added to alkenes ? (1)

A

Gases bubbled through alkene

168
Q

Describe the reaction yield of hydration reactions of alkenes (1)

A

Low

169
Q

How can the reaction yield of hydration reactions undergone by alkenes be improved ? (1)

A
  • recycle untested alkene gas
170
Q

what are addition polymerisation (2)

A
  • individual alkenes
  • join to form polymers
171
Q

what is an advantage of synthetic polymers ? (1)

A

very unreactive

172
Q

what is a problem caused by the unreactivity of synthetic polymers ? (2)

A
  • arent biodegradable
  • hard to dispose of
173
Q

how much plastic waste is produced each year in the UK ? (1)

A

2 million tonnes

174
Q

what is the name of the reaction that turns alkenes into polymers ? (1)

A

addition polymerisation

175
Q

describe the benefit of many plastics being unreactive (2)

A
  • plastic windows dont rot
  • food doesnt react w PTFE coating on pans
176
Q

state 3 ways we can get rid of waste whilst minimising environmental damage (3)

A
  • landfill
  • reusing
  • incineration
177
Q

when are plastics usually landfilled ? (3)

A
  • difficult to seperate from other waste
  • not in enough quantities to make seperation financially worthwhile
  • to difficult to recycle
178
Q

explain the processes undergone by plastics for them to be reused (2)

A
  • recycling
  • cracked into monomers
179
Q

explain how plastics are recycled (2)

A
  • melting
  • remoulding
180
Q

what can the monomers which plastics have been cracked into then be used for ? (2)

A
  • used as organic feedstock
  • to make more plastics
    • other chems
181
Q

why does it make sense to reuse plastics as much as possible ? (1)

A

many plastics made from non renewable oil - fractions

182
Q

what can the heat produced during the incineration of plastics be used for ? (1)

A

generate electricity

183
Q

why does the process of incineration need to be carefully controlled ? (1)

A
  • reduce toxic gases
184
Q

how are toxic gases reduced during the burning of polymers (3)

A
  • waste gases passed through scrubbers
  • gas reacts w a base
  • neutralising gas
185
Q

name a polymer which contains chlorine (1)

A

PVC

186
Q

name the toxic waste gas which will be released by PVC during incineration (1)

A

HCl

187
Q

what are biodegradable polymers ? (1)

A
  • polymers that naturally decompose
188
Q

what can biodegradable polymers be made from (2)

A
  • renewable raw materials
  • oil fractions
189
Q

give an example of a renewable raw material which biodegradable polymers may be made from (1)

A

starch

190
Q

give an example of an oil fraction which biodegradable polymers may be made from (1)

A

hydrocarbon isoprene

191
Q

give a disadvantage of biodegradable polymers (1)

A

more expensive than non - biodegradable polymers

192
Q

why could biodegradable polymers not simply perish away in a landfill (2)

A
  • lack of oxygen
  • lack of moisture
193
Q

explain how biodegradable polymers are very specific (1)

A
  • need certain conditions to decompose
194
Q

name an evnvironemnet where biodegradable polymers will be able to decompose (1)

A
  • compost heap
195
Q

name a potential use of biodegradable polymers (1)

A
  • plastic sheeting used to protect plants from frost
196
Q

explain why biodegradable polymers can decompose quickly by themselves (1)

A

organisms can digest them

197
Q

what are photodegradable polymers ? (1)

A

polymers that decompose when exposed to sunlight

198
Q

Draw and name the monomer, repeating unit and polymer for the alkene propene

A
199
Q
A
200
Q

Describe and explain the shape of alkenes (4)

A
  • trigonal planar
  • 3 bonding regions
  • no lone pairs
  • 120 degree bond angle
201
Q

What type of alkenes do not follow the general formula of CnH2n ? (2)

A
  • cyclic alkenes
  • alkenes w more than 1 double bond
202
Q

What bonds are found in alkenes ? (2)

A
203
Q

When is a sigma bond formed ? (1)

A
  • when 2 S orbitals overlap
204
Q

When is a pi bind formed ? (2)

A
  • sideways overlap
  • of 2 adjacent p orbitals
205
Q

Describe the effect of the formation of the pi bind in an alkene (2)

A
  • creates an area of e- density
  • above and below plane of carbon atoms
206
Q

Which bond, pi bonds or sigma bonds are weaker ? (1)

A

Pi bonds

207
Q

Explain why pi bonds are weaker than sigma bonds (4)

A

-electron density is spread out below and above nuclei
- weaker electrostatic attraction between nuclei + bonded pair of e-s
- lower bond enthalpy
- less energy needed to overcome

208
Q

How many sigma bonds is one carbon atom in an alkenes involved in ?

A

3

209
Q

How many pi bonds does one carbon atom in an alkene form ?

A

1

210
Q

Which bind breaks when an alkene reacts ?

A

Pi bond

211
Q

Which is more reactive alkanes or alkenes ?

A

Alkenes

212
Q

Explain why alkanes don’t react easily (3)

A
  • only contain C-H or C-C sigma bonds
  • sigma bonds have high bind enthalpy so hard to overcome
  • bonds are non polar so don’t attract nucleophile or electrophiles
213
Q

Explain why alkenes are more reactive than alkanes (5)

A
  • the carbon carbon double bond contains both a sigma and a pi bind
  • e- density of pi bind spread out below nuclei
  • weaker electrostatic FOA between nuclei and bonded pair of e-s
  • lower bond enthalpy so easier to overcome
  • pi bond likely to be attacked by electrophiles
214
Q

What organic compound is used as the starting point for making petrochemicals ? (1)

A

Alkenes

215
Q

Why are alkenes used as the star ting point for making petrochemicals ? (1)

A
  • double bond is so reactive
216
Q

Label the pi bond and the sigma bonds on this alkene

A

a level chemistry (9 decks)

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