N2A - Homologous series Flashcards
(136 cards)
1
Q
What is a family of compounds known as?
A
a homologous series
2
Q
What are hydrocarbons?
A
compounds that contain hydrogen and carbon only
3
Q
What are the alkanes?
A
the alkanes are a homologous series of saturated hydrocarbons where all carbon to carbon bonds are single covalent bonds
4
Q
What is the first member of the alkane homologous series?
A
Methane
5
Q
What is the second member of the alkane homologous series?
A
Ethane
6
Q
What is the third member of the alkane homologous series?
A
Propane
7
Q
What is the fourth member of the alkane homologous series?
A
butane
8
Q
What is the fifth member of the alkane homologous series?
A
pentane
9
Q
What is the sixth member of the alkane homologous series?
A
hexane
10
Q
What is the seventh member of the alkane homologous series?
A
heptane
11
Q
What is the eight member of the alkane homologous series?
A
octane
12
Q
What is the molecular formula for methane?
A
CH4
13
Q
What is the molecular formula for ethane?
A
C2H6
14
Q
What is the molecular formula for propane?
A
C3H8
15
Q
What is the molecular formula for butane?
A
C4H10
16
Q
What is the molecular formula for pentane?
A
C5H12
17
Q
What is the molecular formula for hexane?
A
C6H14
18
Q
What is the molecular formula for heptane?
A
C7H16
19
Q
What is the molecular formula for octane?
A
C8H18
20
Q
Physical state of methane at room temp?
A
gas
21
Q
Physical state of ethane at room temp?
A
gas
22
Q
Physical state of propane at room temp?
A
gas
23
Q
Physical state of butane at temp?
A
gas
24
Q
Physical state of pentane at temp?
A
liquid
25
Physical state of hexane at temp?
liquid
26
Physical state of heptane at temp?
liquid
27
Physical state of octane at temp?
liquid
28
Full structural formula for butane?
H H H H | | | | H---C---C---C---C---H | | | | H H H H
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Shortened structural formula of butane
CH3CH2CH2CH3 OR CH3(CH2)2CH3
30
General formula for the alkanes
CnH2n+2
31
What are examples of physical properties?
-melting points -boiling points -viscosity -colour
32
Describe the physical properties of the alkanes
for the melting and boiling point data for alkanes, there is a gradual increase from methane to octane. longer chains have higher melting and boiling points as bigger molecules have stronger forces of attraction between them and so it takes more energy to separate the bigger alkane molecules from each other they are insoluble in water
33
What are the alkanes used for?
they are used as fuels
34
When alkanes burn completely what do they produce?
Carbon dioxide and water CH4 + O2 ----\> CO2 + H20
35
What are the common features of the alkane homologous series?
same general formula similar properties- they all burn show a gradual change in physical properties - boiling points increase as the alkane molecules increase in size
36
What are known as isomers
compounds that have the same molecular formula but different structural formulae are known as isomers
37
What different things do isomers have?
Isomers have different physical properties
38
As the alkanes become larger in size what happens to isomers
the number of isomers fore each alkane increases too e.g. pentane has three isomers and hexane has five isomers
39
What are the rules for naming branched alkanes?
Identify the longest chain of carbon atoms and name the alkane with this number of carbon atoms identify the branch and name it according to the number of carbon atoms in the branch number the branch so that it has the lower of two possible numbers (what carbon atom it comes off)
40
When there is only one branch what is the name, the structure of the branch?
methyl -CH3
41
When there is only two branches what is the name, the structure and the prefix of the branch?
ethyl -C2H5 di
42
When there is only three branches what is the name, the structure and the prefix of the branch?
propyl -C3H7 tri
43
If there were two methyl branches what prefix would we add?
di
44
If there is only one way to draw a branch (such as methylbutane) what do we not need to do?
Use a number to indicate from which carbon atom it stems off
45
If there are two methyl branches on the third and fourth carbon atom how would we write the formula (for hexane)?
3,4 dimethylhexane
46
Definition of physical properties within homologous series'
something that can be observed or measured e.g. melting and boiling points, viscosity and colour
47
What are the cycloalkanes?
a homologous series of hydrocarbons where the carbon atoms join together to form a closed ring
48
Name the cycloalkanes
cyclopropane cyclobutane cyclopentane cyclohexane cyclohexane cyclooctane
49
What is the molecular formula of cyclopropane?
C3H6
50
What is the molecular formula of cyclobutane?
C4H8
51
What is the molecular formula of cyclopentane?
C5H10
52
What is the molecular formula of cyclohexane?
C6H12
53
What is the molecular formula of cycloheptane?
C7H14
54
What is the molecular formula of cyclooctane?
C8H16
55
What state at room temperature is cyclopropane?
gas
56
What state at room temperature is Cyclobutane?
gas
57
What state at room temperature is Cyclopentane?
liquid
58
What state at room temperature is Cyclohexane?
liquid
59
What state at room temperature is Cycloheptane?
liquid
60
What state at room temperature is Cycoloctane?
liquid
61
Draw the shortened structural formula of cyclopropane
62
Draw the full structural formula of cyclopropane
63
Draw the full strucutral formula of cyclobutane
64
Draw the shortened structural formula of cyclobutane
65
Draw the full structural formula of cyclopentane
66
Draw the shortened structural formula of cyclopentane
67
Draw the full structural formula of cyclohexane
68
Draw the shortened structural formula of cyclohexane
69
Draw the full structural formula of cycloheptane
70
Draw the shortened structural formula of cycloheptane
71
Draw the full structural formula of cyclooctane
72
Draw the shortened structural formula of cyclopentane
73
What is the general formula of the cycloalkanes
74
Desribe the physical properties of the alkanes
75
Describe the chemical properties of the cycloalkanes
76
What are the uses of the cycloalkanes ?
can be used as fuels but most are used to make other compounds
77
Draw the full structural formula of cyclopropane
78
Draw the full strucutral formula of cyclobutane
79
Draw the shortened structural formula of cyclobutane
80
Draw the full structural formula of cyclopentane
81
Draw the shortened structural formula of cyclopentane
82
Draw the full structural formula of cyclohexane
83
Draw the shortened structural formula of cyclohexane
84
Draw the full structural formula of cycloheptane
85
Draw the shortened structural formula of cycloheptane
86
Draw the full structural formula of cyclooctane
87
Draw the shortened structural formula of cyclopentane
88
What are the alkenes?
89
What is the general formula for the alkenes ?
90
What does the fact that the cycloalkanes and the alkenes have the same general formual allow us to conclude?
91
What is the names of the alkenes?
92
What is the shortened structural formula of ethene?
93
What is the shortened structural formula of propene?
94
What is the shortened structural formula of hexene?
95
How can we work out the molecular formula for the alkenes?
96
Ethene State at room temperature
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Propene state at room temperature
gas
98
butene stateat room temperature?
99
penetene state at roomt temperature
100
hexene state at room temperature
101
heptene state at room temperature
102
octene state at room temperature
103
What temperature is room temperature ?
25C
104
Draw the full structural formula of ethene
105
Draw the full structural formula of propene
106
Draw the full structural formula of hexene
107
How can alkenes also form isomers?
108
how are the isomers of alkenes named?
109
How do we name an alkenes isomers
we insert the
110
How do we name an alkene's iosmers when there are alos branches
where there are branches, the double bond takes priority over the branch
E.G
4-methlypent2ene
111
Name this:
112
What is the general formula for the alkenes?
113
What does *"saturated"* mean?
114
When there is multiple double bonds in an alkene what is used to indicated the number of double bonds
a prefix is used
diene for two double bonds
triene for three double bonds
115
Describe the physcial properties of the alkenes
their melting and boiling points increase
they are insoluble in water
they burn to produce Co2 and H2O
Unsaturated
116
What does unsaturated mean in chemistry
a compound that can have more atoms added to it. It will contain at least one carbon-to-carbon double bond
117
What does the presence of the carbon-to-carbon double bond allow alkenes to take part in ?
reactions knowm as addition reactions, where reacting molecules can 'add' across the reactive double bond as shown in the diagram below
118
What is an addition reaction?
a chemical reaction where molecules add across a double bond
119
What do alkenes produce wen they react with hydrogen gas
alkanes
120
Draw propene reacting with hydrogen gas to produce propane
121
What is the name of the reaction involving alkenes reacting with hydrogen gas to produce alkanes?
122
Define hydrogenation
an addition reactoin where hydrogen is added across a double bond (alkene - alkane)
123
Following a hydrogenation reaction, is alkane said to be saturated or unsaturated - justify your answer
saturated becuase no more atoms can be added to the molecule
124
What is a convenient labratory test for the presence of double bonds in a moelcule
shake the compound with bromine solution
alkenes cause the bromine solution to decoularise rapidy
with alkanes and cycloalkanes the bromine does not decoularise rapidly
the reaction with the alkene with bromine solution is an other example of an addition reaction: the bromine molecule adds across teh double bond of teh alkene
125
Describe alkenes reacting with the halogens
126
What is formed when alkenes are made to react together?
Alkenes can be made to react with eachother to form very large compounds known as polymers
E.G.
ethene molecules can react with other ethene molecules to form polyethene
127
What are polymers
a very large molecuel formed by the joining together of many smaller molecules (monomers)
128
What is hydration
a chemical reaction in which a molecule of water is added to an unsaturated hydrocarbon producing an alcohol
129
What is a homologous series
a group of molecules with the same general formula and similar chemical properties
130
What is fractional distillition
crude oil is a collection of hydrocarbons and during fractional distillition the crude oil is heated up and as each hydrocarbon has a idfferent boiling point they can be collected individually
this results in long useless hydrocarbonc ahins
131
Cracking hydrocarbons
cracking turns long saturated hydrocarbosn into two smaller hydrocarbons where one is saturated and the other is unsaturated
It is unsaturated as their is not enough hydrogens to make two alkanes
132
What do we use for petrols
short saturated molecules
133
What do we use for plastics
short unsaturated molecules
134
What do we need to remember in the experiment during crude oil
Before removing the heat from the delivery tube lift the delivery tube out of the bromine solution to prevent suck back
135
When one burns a hydrocarbon what is produces
CO2 which is linked to global warming and to climate change
136
