chemistry topic 7 organic chemistry Flashcards
(148 cards)
1
Q
what is a hydrocarbon?
A
any compound that is formed from carbon and hydrogen atoms only
2
Q
what is the general alkane formula?
A
CnH2n+2
3
Q
what are the first four alkanes ?
A
methane ethane propane butane
4
Q
what does it mean when the hydrocarbons are shorter regarding their viscosity?
A
their less viscous
5
Q
the shorter a hydrocarbon chain the more volatile it is what does this mean?
A
it turns into a gas at a lower temperature (lower its boiling point)
6
Q
the shorter a hydrocarbon is the easier it is to set fire to it? what is the word for this?
A
flammable
7
Q
what is the equation for the complete combustion of any hydrocarbon with oxygen?
A
hydrocarbon + oxygen = carbon dioxide + water
8
Q
what happens to the carbon and hydrogen from the hydrocarbon in combustion?
A
they are oxidised ( gain oxygen)
9
Q
what are hydrocarbons used as?
A
fuels
10
Q
why are hydrocarbons used as fuels?
A
due to the amount of energy released when they combust completely
11
Q
what is used to separate crude oil?
A
fractional distillation
12
Q
what is crude oil?
A
a fossil fuel formed by the remains of plants and animals , mainly plankton
13
Q
where is crude oil found and drilled up from?
A
rocks
14
Q
what is fractional distillation used to do?
A
separate hydrocarbon fractions
15
Q
what is crude oil a mixture of?
A
loads of different hydrocarbons
16
Q
what happens first in fractional distillation?
A
the oil is heated until most of it has turned into gas
17
Q
in fractional distillation where do the new gases go?
A
into the fractionating column
18
Q
in fractional distillation, what do the longer hydrocarbons have?
A
high boiling points
19
Q
in fractional distillation, where do the long hydrocarbons condense back into liquids in drain out of the column?
A
they drain out of the column early on , when they’re near the bottom
20
Q
in fractional distillation, what do the shorter hydrocarbons have ?
A
lower boiling points
21
Q
in fractional distillation, where do the shorter hydrocarbons condense and drain out?
A
much later on, near the top of the column where its cooler as they don’t have boiling points as high
22
Q
what is the end result of fractional distillation?
A
each fraction contains a mixture of hydrocarbons that all contain a similar amount of carbon atoms
23
Q
what does oil provide the fuel for?
A
most modern transport
24
Q
what industry uses hydrocarbons to make new compounds for use in things like polymers, solvents etc?
A
the petrochemical industry
25
what are two examples of families in the homologous series?
alkanes and alkenes
26
why are short hydrocarbon chains good for making fuels in high demand?
they are highly flammable
27
why are long chain hydrocarbon not useful for making fuels in high demand?
they form thick gloopy liquids like tar
28
as a result of long chain hydrocarbons being not useful what normally happens?
they are turned into smaller , more useful ones by a process called cracking
29
what is cracking?
a thermal decomposition reaction
30
what is cracking via thermal decomposition?
breaking down molecules by heating them
31
what happens first in cracking via thermal decomposition?
heat and turn the long chain hydrocarbons into gas
32
in thermal decomposition, what happens to the vapour(gas)?
the vapour can be passed over a catalyst
33
what happens when the gas passes over the catalyst?
the long chain molecules split apart on the surface on the specks of catalyst
34
what type of cracking is this when using a catalyst?
catalyst cracking
35
what is steam cracking?
when you vaporise the hydrocarbons, mix them with steam and heat to a very high temperature
36
why are alkenes unsaturated?
they have a double carbon-carbon bond
37
what are the first four alkenes?
ethane, propene, butane and pentene
38
what is the general formula for alkenes?
CnH2n
39
in alkenes how many double bonds does there have to be?
1
40
when you burn alkenes in air instead of oxygen what happens?
incomplete combustion
41
what is incomplete combustion?
as well as carbon dioxide and water produced from combustion you can also get carbon and carbon monoxide
42
what does incomplete combustion result in?
a smoky yellow flame and less energy being released compared to complete combustion of the same compound
43
the equation for incomplete combustion always has to be what?
balanced
44
what happens when orange bromine water is added to a saturated compound?
no reaction will happen and it will stay bright orange
45
what are plastics made up of?
long-chain molecules called polymers
46
what are polymers normally based on?
carbon based
47
what are most monomers made up of?
alkenes
48
what do the monomers that make up addition polymers have?
a double covalent bond
49
what is addition polymerisation?
lots of unsaturated alkenes can open up their double bonds and join together to form polymer chains
50
what is the formula of ethene?
C2H4
51
what is the formula of propene?
C3H6
52
what is the formula of butene?
C4H8
53
what is the formula of pentene?
C5H10
54
in a large amount of oxygen what do alkenes do?
combust completely
55
when alkenes are burned in air what tends to happen?
incomplete combustion
56
what is produced from complete combustion of alkenes?
only water and carbon dioxide
57
what is produced from incomplete combustion of alkenes?
carbon dioxide water carbon monoxide and carbon
58
what is the standard equation for the incomplete combustion of alkenes?
alkene + oxygen = carbon+ carbon monoxide+ carbon dioxide+ water
59
what does incomplete combustion result in ?
a smoky yellow flame, and less energy being released in comparison to complete combustion of the same compound
60
what do the products of incomplete combustion depend on?
how much oxygen is present
61
what is a functional group?
a group of atoms in a molecule that determines how that molecule typically reacts
62
what functional group do all alkenes have?
double carbon CC bond
63
most of the time how do alkenes react?
via addition reactions
64
what happens in an addition reaction?
the carbon carbon double bond will open up to leave a single bond and a new atom is added to each carbon
65
what is addition of hydrogen knows as?
hydrogenation
66
how does hydrogen react with alkenes?
the hydrogen opens up the double bond to form the equivalent, saturated, alkane
67
in hydrogenation when does the alkene react?
in the presence of a catalyst
68
how do halogens react with alkenes?
the molecules formed re saturated, with the CC carbons each becoming bonded to a halogen atom
69
how do bromine and ethene react together?
to form dibromoethane
70
what can be used to test for alkenes?
the addition of bromine to a double bond
71
how do you use bromine to test for alkenes?
the bromine will add across the double bond, making a colourless dibromo-compound
72
what happens when bromine is added to a saturated compound?
no reaction will happen and it will stay bright orange
73
when alkenes react with steam what happens?
water is added across the double bond and an alcohol is formed
74
how is ethanol made?
mixing ethene with steam and passing it over a catalyst
75
how is ethanol made industrially?
after the reaction, the reaction mixture is passed into a condenser. Ethanol and water have a higher boiling point than ethene so both condense whilst any unreacted ethene is recycled back into the reactor. The alcohol is then purified in fractional distillation
76
what are polymers?
long molecules formed when lots of small molecules called monomers join together
77
what do polymers usually make up?
carbon based plastics
78
what are monomers usually in alkenes?
alkenes
79
what are the monomers that make up additional polymers made of?
double covalent bond
80
what is addition polymerisation?
when unsaturated molecules open up their double bonds and join together to form polymer chains
81
when monomers react in addition polymerisation what is the only product?
the polymer, so an addition polymer contains exactly the same type and number of atoms as the monomers that formed it
82
how do you draw the displayed formula of an addition polymer from the displayed formula of its monomer?
draw the two alkene carbons, replace the double bond with a single bond and add an extra single bond to each carbon. fill in surrounding group the same and add brackets with repeating units n at bottom right
83
how do you get the displayed formula of the polymer to the displayed formula of the monomer?
draw out the repeating bit of the polymer, get rid of the two bonds going out through the brackets and add a double bond to the carbons
84
what is the general formula of an alcohol?
CnH2n+1OH
85
what is an alcohol with 2 carbons?
C2H5OH
86
all alcohols contain what group?
OH group
87
how do you draw alcohols?
draw your C with H bonds and an OH bond
88
what are the four first alcohols?
methanol, ethanol, propanol and butanol
89
what property do alcohols have?
they are very flammable
90
what kind of combustion do alcohols undergo In air?
complete combustion to produce carbon dioxide and water
91
what relationship does methanol, ethanol, propanol and butanol have with water?
they are soluble
92
what ph does methanol, ethanol, butanol and propanol have in their solutions?
neutral
93
what do the first four alcohols react with and what product does the reaction produce?
sodium and the product is hydrogen
94
what do alcohols produce when they are oxidised?
a carboxylic acid
95
different alcohols form different carboxylic acids. what do methanol and ethanol form?
methanoic acid and ethanoic acid
96
why are alcohols such as methanol and ethanol used as solvents in industry?
they can dissolve most things water can dissolve but also what water cant dissolve (hydrocarbons oils and fats)
97
the first four alcohols are used as fuels. what are some examples of this?
ethanol is used in spirit burners as it burns cleanly and non smelly
98
how is ethanol usually made?
via fermentation
99
what does fermentation use?
an enzyme in yeast to convert sugars to ethanol. carbon dioxide is produced
100
what is the equation for fermentation?
sugar with arrow plus yeast= ethanol + co2
101
in what conditions does fermentation happen fastest?
temps of around 37 degrees in a slightly acidic solution under anaerobic conditions (no oxygen)
102
why does it work best under these conditions?
under these conditions the enzyme in yeast works best and if the conditions were different the enzyme could work slower or denature
103
what functional group are carboxylic acids?
COOH
104
what names do carboxylic acids end in?
anoic acid
105
what is the formula for methanoic acid?
HCOOH
106
what is the formula for ethanoic acid?
CH3COOH
107
what is the formula for propanoic acid?
C2H5COOH
108
what is the formula for butanoic acid?
C3H7COOH
109
how do carboxylic acids react?
like other acids, with carbonates to produce salt, water and co2
110
what names do the salts form with carboxylic acids?
ending in anoate
111
what happens when carboxylic acids dissolve in water?
they ionise and release H+ ions resulting in an acidic solution
112
what does it mean when carboxylic acids don't ionise completely?
they just form weak acidic solutions meaning they have a higher PH than aqeous solutions of strong acids with the same concentration
113
what can be made from carboxylic acids?
esters
114
what functional group do esters have?
COO
115
what are esters formed from?
an alcohol and carboxylic acid
116
what sort of catalyst is usually added to make an ester?
acid catalyst
117
what is the equation for making an ester?
alcohol + carboxylic acid = plus catalyst ester +water
118
what can be made from ethanoic acid and ethanol with a catalyst?
Ethyl ethanoate
119
what does condensation polymerisation involve?
monomers which contain different functional groups
120
what happens to the monomers in condensation polymerisation?
the monomers react together and bonds form between them, making polymer chains
121
for each new bond formed in condensation polymerisation what happens?
a small molecule (for example, water) Is lost. this is why its called condensation polymerisation
122
what is the simplest type of condensation polymers?
contains two different types of monomer, each with two of the same functional groups
123
how can a polyester be made by condensation polymer?
a diol (ethane diol)+ a dicarboxylic acid (hexanedioic acid) gives a polyester + water
124
how many numbers of types of monomers are there in addition polymerisation?
only one type of monomer containing a double carbon bond
125
how many number of products is there from addition polymerisation?
only one product fromed
126
how many functional groups are involved in polymerisation?
carbon carbon double bond in monomer
127
how many number of types of monomers are there in condensation polymerisation?
two monomer types each containing two of the same functional groups or one monomer type with two different functional groups
128
how many number of products are made from condensation polymerisation?
two types of product- the polymer and a small molecule (e.g. water)
129
how many functional groups are involved In condensation polymerisation?
two reactive groups on each monomer
130
where are polymers found apart from the lab?
the natural world
131
what two functional groups does an amino acid contain?
a basic amino acid group(NH2) and an acidic carboxyl group(COOH)
132
what is an example of an amino acid?
glycine- the smallest and simplest amino acid possible
133
what polymers can amino acids form?
polypeptides via condensation polymerisation
134
how can amino acids form a polymer chain?
the amino group of an amino acid can react with the acid group of another, and so on, to form a polymer chain
135
for every new bond formed in amino acids what is lost?
water
136
what are proteins known as?
one or more long chains of polypeptides
137
what important uses to proteins have in the body?
enzymes work as catalysts, haemoglobin transports oxygen, antibodies from part of the immune system and the majority of body tissue is made from proteins
138
polypeptides and proteins can contain what?
different amino acids in their polymer chains
139
where is DNA found?
in every living thing and many viruses
140
what does DNA contain?
genetic instructions that allow the organism to develop and operate
141
what is the structure of DNA like?
a large molecule that takes a double helix structure
142
what is DNA made of?
two polymer chains of monomers called nucleotides
143
what does each nucleotide contain?
a small molecule known as a base. there are four different bases known as ACGT
144
what do the bases on each polymer chain do with each other?
pair up and form cross links keeping the two strands of nucleotides together and giving the double helix structure
145
what does the order of bases act as?
a code for an organisms genes
146
what are sugars?
small molecules that contain carbon, oxygen and hydrogen
147
what do sugars react together through polymerisation to form?
large polymers eg starch and cellulose
148
what gives proteins different properties and shapes?
the order of amino acids
