module 4 section 1 - basic concepts and hydrocarbons Flashcards
1
Q
what is a homologous series ? (1)
A
family of compounds with similar chemical properties
2
Q
name the first 4 alkanes (4)
A
- methane
- ethane
- propane
- butane
3
Q
Draw the functional group of an alkene
A
4
Q
Draw the functional group of alcohol
A
5
Q
Draw the functional groups of a halo alkane
A
6
Q
Draw the functional group of an aldehyde
A
7
Q
Draw the functional group of a ketone
A
8
Q
Draw the functional group of a carboxylic acid
A
9
Q
What is the suffix of an alkene?
A
- ene
10
Q
What is the suffix of an alcohol?
A
-ol
11
Q
What is the suffix of an aldehyde? 
A
-al
12
Q
What is the suffix of a ketone? 
A
-one
13
Q
What is the suffix of a carboxylic acid? 
A
-oic acid
14
Q
What is an organic compound ? (1)
A
All contain element carbon
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
16
Q
What is a saturated hydrocarbon ? (1)
A
-single bonds only
17
Q
What is an unsaturated hydrocarbons ? (1)
A
One or more C=C
18
Q
What is a homologous series ? (1)
A
Family of compounds w similar chemical properties
19
Q
When is an organic molecules functional group responsible for ? (1)
A
- responsible for mlcls chemical properties
20
Q
What 3 ways can hydrocarbons be classified as ? (3)
A
- aliphatic
- alycylic
- aromatic
21
Q
What is an aliphatic hydrocarbon ?(3)
A
- carbon atoms joined to each other
- in unbranched or branched chains
- or non aromatic rings
22
Q
What is an alycylic hydrocarbon (3)
A
-carbon atoms joined to each other
- in ring structures
- with or without branches
23
Q
What is an aromatic hydrocarbon ? (2)
A
- some or all carbon atoms
- Found in a benzene ring
24
Q
What are the 3 homologous series of aliphatic hydrocarbons (3)
A
- alkanes
- alkenes
- alkynes
25
What are alkanes ? (1)
- contain C-C bonds
26
What are alkenes ? (1)
Contain at least 1 C=C
27
What are alkynes ? (1)
Contain at least 1 triple carbon - to - carbon bond
28
What type of hydrocarbon is shown here ?
Aliphatic
29
What type of hydrocarbon is shown here ?
Alicylic
30
What type of hydrocarbon is shown here ?
Aromatic
31
What prefix is used when naming cycloalkanes ? (1)
Cyclo
32
State the functional group in this molecule
Chloroalkane
33
State the functional group in this molecule
Ketone
34
State the functional group in this molecule
Alcohol
35
State the functional group in this molecule
Bromoalkane
36
what are the 2 types of bond fission ? (2)
- homolytic fission
- heterolytic fission
37
what do bond fissions do ? (1)
break cov bonds
38
what happens during a homolytic fission (3)
- each of bonded atoms takes one e- from shared pair from bond
- each atom now has single unpaired e-
- forming a radical
39
what is a radical ? (2)
- atom or groups of atoms
- with an unpaired e-
40
what happens during a hetrolytic fission (3)
- 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
41
what is a reaction mechanism ? (1)
how a reaction takes place
42
what do curly arrows in reaction mechanisms show ? (2)
- movement of electrons
- when bonds are being broken or made
43
what does a full headed arow show ? (2)
- movement of a pair of e-
- when bonds are being broken or made
44
what does a half headed arrow show ? (2)
- movement of single unpaired e-
- in mechanisms involving radicals
- when bonds are being broken or made
45
what are the 3 types of reaction ? (3)
- addition
- substitution
- elimination
46
what is an addition reaction (2)
- 2 reactions join
- to form 1 product
47
what is a substitution reaction (2)
- atom or group of atoms replaced
- by diff atoms or group of atoms
48
what is an elimination reaction ? (2)
- removal of a small mlcl from a larger one
- 1 reactant, 2 products
49
Draw the homolytic fission of the carbon carbon bond in methane
50
Draw the hetrolytic fission of the carbon - chlorine bind in Chloromethane
51
Use a curly arrow to show the movement of a pair of electrons in the hetrolytic fission of the carbon - chlorine bind in chloromethane
52
Draw the reaction mechanism for the homolytic fission of a carbon - hydrogen bond in Methane
53
What type of reaction is shown here ?
Addition
54
What type of reaction is shown here
Substitution
55
What type of reaction is shown here
Elimination
56
Show the homolytic fission of a chlorine - chlorine bind in a chlorine atom
57
describe the bonding in alkanes (2)
- saturated hydrocarbons- single bonds
- bonds called sigma bonds
58
what is a sigma bond ? (3)
- single cov bond
- formed by direct overlap of orbitals
- between bonding atoms
59
describe the shape of alkanes (5)
- 4 bond regions
- 0 lone pairs
- tetrahedral
- 109.5 degrees
- bonded pairs repel eachother equally
60
what is the strongest intermolecular force found in an alkane ?
IDDI ( london forces)
61
describe the polarity of alkanes (1)
non polar
62
describe the trends in BP's of alkanes (5)
- 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
63
compare the BP's of branched alkanes and their straight chain counterpoints (4)
- branched have lower BP
- as fewer surface points of contact
- so weaker IDDI
- so less energy needed to overcome
64
define homologous series (2)
- a family/series/groups of mlcls w same functional group
- each successive member differs by CH2
65
write the general formula of cycloalkanes (1)
CnH2n+2
66
describe the reactivity of alkanes (2)
- unreactive because C-C and C-H sigma bonds are strong
- bonds arev unreactive
67
what 2 reactions can be undergone by alkanes ? (2)
- combustion
- free radical substitution
68
what are the products of complete combustion of an alkane ?
CO2 and H20
69
what are the 2 possible product combinations on an incomplete conbustion of an alkane (2)
- CO and H2O
- C and H2O
70
write the balanced equation for the complete combustion of butane including state symbols
CH3CH2CH2CH3 (g) + 6.5O2 (g) = 4CO2 (g) + 5H2O (l)
71
in what order of elements should you balance in a complete and incomplete combustion ?
C H O
72
write the balances symbol equation for the incomplete combustion of butan to produce carbon monoxide
CH3CH2CH2CH3 (g) + 4.5O2 (g) = 4CO (g) + 5H2O (l)
73
write the balances symbol equation for the incomplete combustion of butan to produce carbon monoxide
CH3CH2CH2CH3 (g) + 2.5O2 (g) = 4C (g) + 5H2O (l)
74
state one issue caused by the production of carbon in incomplete combustion
global dimming
75
what is the state symbole of most alkanes ?
(g)
76
what is the state symbol of heptane ?
(l)
77
what is an isomer ? (2)
- same Mr
- diff atom arrangement
78
what are the 2 types of isomers ? (2)
- structural isomers
- stereoisomers
79
what are structural isomers ? (2)
- same Mr
- diff structural formula
80
what are the 3 types of structural isomers ? (3)
- chain isomers
- positional isomers
- functional group isomers
81
what are chain isomers ? (1)
- carbon skeleton arranged differently
82
what are positional isomers ? (3)
- same skeleton
- same functional group
- functional group attached to diff carbon atom
83
what are functional group isomers ? (1)
- same stoms arranged into diff functional groups
84
explain the properties of chain isomers (3)
- similar chem properties
- diff physical properties eg BP
- because of change in shape of mlcl
85
explain the properties of positional isomers (2)
- diff physical properties
- diff chem properties
86
explain the properties of functional group isomers (2)
- very diff chem properties
- very diff physical properties
87
what type of isomers are shown here (2)
- structural
- chain isomers
88
what type of isomers are shown here ? (2)
- structural
- positional isomers
89
what type of isomers are shown here ? (2)
- structural
- functional group isomers
90
what is the functional group in 2-methylpentan-1-ol and why is it necessary to state its position on the carbon chain ? (3)
- OH = hydroxyl
- could be attached to any of 5 carbons
- position of OH affects its chemistry
91
what are stereoisomers ? (2)
- same structural formula
- diff arrangement in space
92
what are the 4 types of stereoisomers ?
- cis
- trans
- E
- Z
93
when can stereoisomers occur ? (2)
- when 2 double bonded C atoms
- each have 2 diff atoms or groups attached to them
94
what is a Z - isomer ?
- groups or atoms with highest atomic number
- on Zame Zide
95
what is an E isomer ? (1)
- groups or atoms with highest atomic number
- on opp sides
96
name a saturated structural isomer of hex-2-ene
cyclohexane
97
place Cl, H, Br and F in order of decreasing priority as indicated by CIP rules (4)
Br>Cl>F>H
98
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)
look at next atom in group
99
how is priority determined in E/Z isomers according to CIP rules ? (1)
larger atomic number = higher priority
100
when can stereoisomers be called Cis or Trans isomers ?
if carbon atoms have at least 1 group in common
101
explain why alkenes can have E/Z isomers but alkanes cannot (2)
- E/Z isomers occur because atoms cant rotate about C=C double bonds
- alkenes contain C=C double bonds but alkanes dont
102
what causes alkenes to form stereoisomers ? (1)
- restricted rotation around C=C double bond
103
what are the saturated structural isomers of straight chain alkenes ? (1)
cycloalkanes
104
what is a nucleophile ? (2)
- atom or group
- donates pair of e- to form new cov bond
105
what is an electrophile ? (2)
- atom of group
- accepts pair of e- to form new cov bond
106
what are nucleophiles attracted to ? (1)
electron deficient centre or atom
107
what are electrophiles attracted to ? (1)
electron rich centre or atom
108
what type of reactions do electrophiles undergo ?
addition
109
what type of reaction do necleophiles undergo ?
substitution
110
what is the mechanism of a substitution reaction undergone by a nucleophile called ? (1)
nucleophilic substitution
111
give 4 examples of nucleophiles (4)
- Br-
- OH-
- H20
- NH3
112
give 3 examples of electrophiles (3)
- Br2
- HBr
- NO2+
113
State the nucleophile shows in this nucleophilic attack
OH-
114
Name the electrophile in this addition reaction
Br2
115
State the nucleophile in this nucleophilic attack
OH-
116
Draw the E and Z isomers of but-2-ene writing their specific names
117
Draw the E and Z isomers for 2-Chloro-but-2-ene including their specific names
118
Name this stereoisomer
Trans-1-Bromopropene
119
Describe the reactions of alkanes with halogens in the dark or at room temperature (1)
No reaction
120
When is an alkane able to react with a halogen? (1)
Presence of uv or sunlight
121
State the products of the reaction between an alkane and a halogen in the presence of sunlight (2)
- Haloalkane
- hydrogen halide
122
Explain now halogenation of an alkane happens (2)
• via homolytic bond fission
. Forming Free radicals
123
Write an equation for the reaction of methane with bromine and state the main product formed (2)
CH4(g) + Br2 (l) = CH3Br(g) HBr(g)
- Bromomethane
124
What are the 3 main steps in the mechanism of a free radical substitution (3)
- Initiation
- propagation
- termination
125
Show the initiation mechanism using bromine
Br2 =2 br•
126
Show the propagation steps using methane and bromine
Br• +CH4 =HBr + •Ch3
•Ch3 + Br2 = CH3Br + Br•
127
Write the termination reactions continuing the reactions of methane with bromine (3)
Br• + Br• = Br2
•CH3 + •CH3 = C2H6
•CH3 + Br• = CH3Br
128
Why are alkanes able to react with halogens in the presence of sunlight (2)
- Uv radiation in sunlight
- provides initial energy for reaction to take place
129
what type of reactions happen to alkenes ? (1)
electrophilic addition reactions
130
what happens when an alkene undergoes an electrophilic addition reaction ? (2)
- double bond opens up
- atoms added to carbon atoms
131
what do electrophiles include ? (2)
- positively charged ions
- polar molecules
132
why do electrophilic addition reactions happen to alkenes ? (2)
- double bond has many electrons
- easily attacked by electrophiles
133
name the electrophilic addition reactions undergone by alkenes (4)
- adding hydrogen
- halogenation (addition of halogens)
- hydration
- addition of hydrogen halides
134
what is the product when an alkene undergoes hydrogen addition ? (1)
alkane
135
describe the conditions required for an alkene to undergo hydrogen addition (2)
- nickel catalyst
- 150 degrees celcius
136
what is the product formed when an alkene undergoes halogenation ? (1)
- dihaloalkane
137
what is the product formed when alkenes undergo hydration ? (1)
alcohol
138
what type of reacion is the alkene hydration ? (1)
reversible reactioons
139
what conditions are reaquired for alkene hydration to take place ? (3)
- high temp around 300 degrees celcius
- high pressure around 60-70 atm
- solid phosphoric (V) acid catalyst
140
describe how alkene hydration takes place (2)
- steam added
- across double bond
141
explain how halogenation is used to test for unsaturation (2)
- shake an alkene w orange bromine water
- = colourless
142
Using displayed formula show the reaction which occurs when ethene undergoes hydrogen addition and name the product formed
Ethane
143
Using structural formula show the reaction undergone when ethene undergoes hydrogen addition
144
Using displayed formula show the halogenation reaction between ethene and chlorine and name the product formed
145
Using displayed formula show the halogenation reaction between propane and bromine and name the product formed
146
Using structural formula write the general equation for the halogenation reaction of alkenes
147
Using ethene and chlorine as an example show the mechanism for the halogenation reaction between them and name the product formed
148
Using structural formula show the hydration reaction undergone by ethene and name the product formed
Ethanol
149
Using ethene as an example show the mechanism for hydration reactions and name the product formed
Ethanol
150
Using displayed formula show the addition of hydrogen halide reaction which takes place when hydrogen bromide reacts with Ethene and name the product formed
151
Show the reaction mechanism for the reaction between ethene and hydrogen bromide
152
Show the reaction mechanism for the reaction between cyclohexane and hydrogen bromide
153
How many products are formed when a hydrogen halide is added to an unsymmetrical alkene ?
2
154
What is an alkyl group ? (1)
A functional group
155
What are the three types of carbocations ? (3)
- primary carbocation
- secondary carbocation
- tertiary carbocation
156
How many alkyl groups does a primary carbocation have ?
1
157
How many alkyl groups is a tertiary carbocation attached to ?
3
158
How many alkyl groups is a secondary carbocation attached to ?
2
159
Which carbocation is the most stable ? (1)
Tertiary carbocation
160
Which carbocation is the least stable ? (1)
Primary carbocation
161
Why is a carbocation which has more alkyl groups more stable that a carbocation which has less alkyl groups ? (2)
- alkyl groups feed electrons towards + charge
- so carbocation more likely to form
162
Using the reaction between hydrogen bromide and propene determine which product is the major product and which product is the minor product
163
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)
- major product - more stable carbocation
- minor product + least stable carbocation
164
Which product is more likely to form when adding a hydrogen halide to an unsymmetrical alkene ? (1)
Major product
165
What is Markownikoff’s rule ? (3)
- 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
What is the product formed when hydrogen halides are added to alkenes ? (1)
Haloalkanes
167
How are hydrogen halides added to alkenes ? (1)
Gases bubbled through alkene
168
Describe the reaction yield of hydration reactions of alkenes (1)
Low
169
How can the reaction yield of hydration reactions undergone by alkenes be improved ? (1)
- recycle untested alkene gas
170
what are addition polymerisation (2)
- individual alkenes
- join to form polymers
171
what is an advantage of synthetic polymers ? (1)
very unreactive
172
what is a problem caused by the unreactivity of synthetic polymers ? (2)
- arent biodegradable
- hard to dispose of
173
how much plastic waste is produced each year in the UK ? (1)
2 million tonnes
174
what is the name of the reaction that turns alkenes into polymers ? (1)
addition polymerisation
175
describe the benefit of many plastics being unreactive (2)
- plastic windows dont rot
- food doesnt react w PTFE coating on pans
176
state 3 ways we can get rid of waste whilst minimising environmental damage (3)
- landfill
- reusing
- incineration
177
when are plastics usually landfilled ? (3)
- difficult to seperate from other waste
- not in enough quantities to make seperation financially worthwhile
- to difficult to recycle
178
explain the processes undergone by plastics for them to be reused (2)
- recycling
- cracked into monomers
179
explain how plastics are recycled (2)
- melting
- remoulding
180
what can the monomers which plastics have been cracked into then be used for ? (2)
- used as organic feedstock
- to make more plastics
- + other chems
181
why does it make sense to reuse plastics as much as possible ? (1)
many plastics made from non renewable oil - fractions
182
what can the heat produced during the incineration of plastics be used for ? (1)
generate electricity
183
why does the process of incineration need to be carefully controlled ? (1)
- reduce toxic gases
184
how are toxic gases reduced during the burning of polymers (3)
- waste gases passed through scrubbers
- gas reacts w a base
- neutralising gas
185
name a polymer which contains chlorine (1)
PVC
186
name the toxic waste gas which will be released by PVC during incineration (1)
HCl
187
what are biodegradable polymers ? (1)
- polymers that naturally decompose
188
what can biodegradable polymers be made from (2)
- renewable raw materials
- oil fractions
189
give an example of a renewable raw material which biodegradable polymers may be made from (1)
starch
190
give an example of an oil fraction which biodegradable polymers may be made from (1)
hydrocarbon isoprene
191
give a disadvantage of biodegradable polymers (1)
more expensive than non - biodegradable polymers
192
why could biodegradable polymers not simply perish away in a landfill (2)
- lack of oxygen
- lack of moisture
193
explain how biodegradable polymers are very specific (1)
- need certain conditions to decompose
194
name an evnvironemnet where biodegradable polymers will be able to decompose (1)
- compost heap
195
name a potential use of biodegradable polymers (1)
- plastic sheeting used to protect plants from frost
196
explain why biodegradable polymers can decompose quickly by themselves (1)
organisms can digest them
197
what are photodegradable polymers ? (1)
polymers that decompose when exposed to sunlight
198
Draw and name the monomer, repeating unit and polymer for the alkene propene
199
200
Describe and explain the shape of alkenes (4)
- trigonal planar
- 3 bonding regions
- no lone pairs
- 120 degree bond angle
201
What type of alkenes do not follow the general formula of CnH2n ? (2)
- cyclic alkenes
- alkenes w more than 1 double bond
202
What bonds are found in alkenes ? (2)
203
When is a sigma bond formed ? (1)
- when 2 S orbitals overlap
204
When is a pi bind formed ? (2)
- sideways overlap
- of 2 adjacent p orbitals
205
Describe the effect of the formation of the pi bind in an alkene (2)
- creates an area of e- density
- above and below plane of carbon atoms
206
Which bond, pi bonds or sigma bonds are weaker ? (1)
Pi bonds
207
Explain why pi bonds are weaker than sigma bonds (4)
-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
How many sigma bonds is one carbon atom in an alkenes involved in ?
3
209
How many pi bonds does one carbon atom in an alkene form ?
1
210
Which bind breaks when an alkene reacts ?
Pi bond
211
Which is more reactive alkanes or alkenes ?
Alkenes
212
Explain why alkanes don’t react easily (3)
- 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
Explain why alkenes are more reactive than alkanes (5)
- 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
What organic compound is used as the starting point for making petrochemicals ? (1)
Alkenes
215
Why are alkenes used as the star ting point for making petrochemicals ? (1)
- double bond is so reactive
216
Label the pi bond and the sigma bonds on this alkene
