unit four: organic chemistry Flashcards
(135 cards)
1
Q
methane molecular formula
A
CH4
2
Q
ethane molecular formula
A
C2H6
3
Q
propane molecular formula
A
C3H8
4
Q
butane molecular formula
A
C4H10
5
Q
pentane molecular formula
A
C5H12
6
Q
what are isomers
A
compounds which have the saem molecular formula but different structural formula
7
Q
what is a homologous series
A
a series of compounds that:
have the same functional group
have similar chemical properties
show a trend (gradation) in physical properties
can be described by the same general formula
differ from the next by a CH2 unit
8
Q
alkane general formula
A
Cn H2n + 2
9
Q
members of the same homologous series show a trend in
A
physial properties
10
Q
members of the same homologous series have
A
similar chemical properties
11
Q
ethene molecular formula
A
C2H4
12
Q
propene molecular formula
A
C3H6
13
Q
but-1-ene molecular formula
A
C4H8
14
Q
what is a hydrocarbon
A
a substance that contains carbon and hydrogen only
15
Q
alkene functional group
A
C=C
16
Q
what does unsaturated in organic chem mean
A
alkene - they contian a C=C bond.
17
Q
what does a saturated compound contain
A
only single C-C bonds
18
Q
what does an unsaturated compound contain
A
contains one or more double or triple C=C bonds
19
Q
alkene general formula
A
CnH2n
20
Q
how do you test for a C=C bond
A
add bromine water and the orange bromine water will be decolourised.
21
Q
how can ethene be produced
A
cracking
22
Q
what is polymerisaton
A
joining up of lots of little molecules (monomers) to make one big molecule (polymer). molecules add onto eachother without anything else being formed. this is called addition polymerisation
23
Q
what is LDPE
A
low density polyethene
24
Q
what is HDPE
A
high density polyethene
25
what is PVC
poly(chloroethene)
26
what temperature does crude oil get heated to
350 degrees celsius
27
pentene molecular formula
C5H12
28
what is the order of hydrocarbons' boiling points in crude oil
```
refinery gases
gasoline
kerosene
diesel oil
fuel oil
bitumen
```
29
uses of refinery gases
natural gas
LPG for domestic heating and cooking
calor gas
30
uses of gasoline
petrol, fuel for cars
31
uses of kerosene
jet fuel, paraffin
32
uses of diesel
diesel, fuel for buses, lorreis, some cars and some railway engines. some is also converted to petrol in cracking,
33
uses of fuel oil
industrial heating oil and fuel for ships
34
uses of bitumen
lubricants, waxes
35
how many carbon atoms are in refinery gases
1-4
36
how many carbon atoms are in gasoline
5-10
37
how many carbon atoms are in kerosene
11-16
38
how many carbon atoms are in diesel
17-20
39
how many carbon atoms are in fuel oil
21-30
40
how many carbon atoms are in bitumen
more than 31
41
what type of bonding holds all organic compounds together
covalent
42
what colour are small alkanes
light
43
what colour are large alkanes
dark
44
viscosity of small alkanes
low
45
viscosity of large alkanes
high
46
boiling point of small alkanes
low
47
boiling point of high alkanes
high
48
are small alkanes volatile
yes
49
are large alkanes volatile
no
50
are small alkanes flammable
high
51
are large alkanes flammable
low
52
are small alkanes useful as a fuel
yes
53
are large alkanes useful as a fuel
no
54
CLEANNESS
OF FLAME
55
FRACTION
DEF
56
what are the two main gases that cause acid rain
sulphur dioxide
| nitrogen dioxide
57
what is the effect of acid rain on trees
stunted growth
58
what is the effect of acid rain on buildings made of limestone or objects made of metal
corrosion
59
how much of crude oil is petrol
about 25%
60
why does cracking produce short chain molecules and an alkene
there aren't enough carbon atoms to form more alkanes and so they are forced to form double bonds
61
what would be observed as bromine reacts with methane
orange to colourless
62
what would be observed as chlorine reacts with methane
pale green to colourless
63
what can organic compounds exist as
chains, branched chains or rings of carbon atoms with hydrogens attatched
64
what is the empirical formula
the simplest whole number ration of the atoms in a compound.
65
what is the molecular formula
the actual number of each type of atom present in a molecule.
66
what is the molecular formula a multiple of
the empirical formula.
67
what are homologous series
a series of compounds with similar chemical properties because they have the same functional group. each member differs from thenext by one -CH2-
68
general formula of alkanes
CnH2n+2
69
what is a funtional group
an atom or group of atonms that determine the chemical properties of a compound.
70
what is a structural formula
shows how the atoms in a molecule are joined together.
71
what is a displayed formula
the full structural formula that shows all the bonds in the molecule as indiviual lines.
72
what does each line represent in a displayed formula
a pair of shared electrons in a covalent bond.
73
what are alkanes
a homologous series of similar hydrocarbons (compounds of carbon and hydrogen only) in which all the carbons are joined to eachother with single covalent bonds.
74
what are alkenes
a homogolous serioes of hydrocarbons which contain a carbon-carbon double bond.
75
side chain -methyl
CH3
76
side chain -ethyl
CH3CH2
77
what is the position of the side chain shown by
by numbering the carbon atoms from the end of the longest chain which produces the smaller numbers in the name
78
what are structural isomers
molecules with the same molecular formula but different structural formulae
79
what are the three isomers for C5H12
pentane
2-methylbutane
2,2-dimethylpropane
80
does ethene have any isomers
no
81
does propene have any isomers
none that are still alkenes
82
what are the isomers of C4H8
but-1-ene
2-methylpropene
but-2-ene
83
what are alcohols
homologous series of compounds which all contain an -OH functional group attatched to a hydrocarbon chain.
84
what are the two different forms of propanol
propan-1-ol
| propan-2-ol
85
why are the two different forms of propanol structural isomers
because there is no way that you can bend or twist one of the molecules to make the other,
86
when does a substitution reaction occur
when an atom or group of atoms is replaced by a different atom or group of atoms.
87
what is an addition reaction
when something is added to a molecules without taking anything away. this happens to alkenes.
88
origins of crude oil
dead plants and animals turning to limestone after being covered in layers of sediment. the soft tissue was gradually changed by heat and high pressure to crude oil
89
is crude oil renewable
no its non-renewable
90
what is crude oil
a mixture of hydrcarbons.
91
explain the trend in volatility in crude oil
the bigger the hydrocarbons, the more slowly it evaporates at room temperature. this is because the bigger molecules are more strongly attracted to their neighbours and so don't turn into a gas so easily
92
which burns easily big hydrocarbons or small hydrocarbons
smaller ones. this limits the use of the bigger ones as fuels
93
trend in colour of crude oil
the liquids become darker in colour as the molecules become bigger
94
fractional distillation of crude oil
it is heated until it boils and the vapours pass into a fractionating column, which is cooler at the top and hotter at the bottom. how far up the column a particular hydrocarbon moves depends on its boiling point.
95
what do all hydrocarbons burn in air/oxygen to form
carbon dioxide and water
96
what is a fuel
a substance that which, when burned, releases heat energy.
97
if there isnt enough air for combustion what happens
incomplete combustion --> soot/carbon and carbon monoxide.
98
why is CO poistionous
it reduces the ability of the blood to carry oxygen around your body.
99
complete combustion equation
Fuel + O2 --> CO2 + H2O
100
environmental problems with burning crude oil-derived fossil fuels
carbon dioxide is produced this causes the greenhouse gas to trap the heat radiated from the earths surface (originally from the sun) and can lead to climate change.
101
when is acid rain formed
when water and oxygen in the atmosphere react with sulfur dioxide to produce sulfuric acid or with various oxides of nitrogen to give nitric acid.
sulfur dioxide and NOx come mainly from power stations and factories burning fossil fuels, or from motor vehicles.
102
why is acid rain bad
it kills trees and fish in lakes (sometimes all the life in the lake) and limestone builidings are damaged.
103
solution to acid rain
removing sulfur from fuels, scrubbing the gases from power stations and factories to remove sulfur dioxide and NOx, and using catalytic converters in cars.
104
problems with fractions
too many long chains hydrocarbons not in demand and not as profitable.
too few shorter chain hydrocarbons that can be used as fuel.
105
what is cracking
the process by which long-chain alkanes are converted to alkenes and shorter-chain alkanes
106
what is the fuel oil fraction passed over
a catalyst of silicon dioxide (silica) and aluminium oxide (alumina)
107
what temperature does cracking occur at
600-700 degrees
108
what process is cracking
thermal decomposition
109
what does cracking produce
a mixture of alkanes and alkenes
110
why do oil companies carry out cracking
to produce more petrol
to produce more alkenes that can be used for making polymers (plastics) (alkenes are more reactive than alkanes and also have other uses)
111
what is polymerisation
the joining up of lots of little molecules (monomers) to make one big molecule (polymer).
112
what is addition polymerisation
molecules add onto eachother without anything elese being formed
113
chain length of the polymerisation of ethene
4000-40,000
114
types of polyethene
LDPE (low density polyethene)
| HDPE (high density polyethene)
115
LDPE is used for
thin film to make polythene bags
| weak
116
HDPE is used for
plastic bottles
| rigid
117
what is polypropene used to make
ropes and crates
118
what does PP mean
polypropene
119
what is PVC
polyvinylchloride, the old name for polychloroethene
120
uses for PVC
water pipes
| replacement windows
121
how can PVC be made flexible
by adding plasticisers
122
why would PVC be made flexible
for sheet floor covering and clothing.
123
does PVC conduct electricity
no so it can be used for electrical insulation
124
what is tetrafluroethene
a molecule derived from ethene in which all four hydrogen atoms are replaced by fluorine.
125
what is poly(tetrafluroethene) known as
Teflon or PTFE
126
what is poly(tetrafluroethene) used for
non stick coating for pots and pans
127
why is PTFE used for non stick linings
it is unreactive due to the strong carbon-fluorine bonds
128
how to work out a monomer from a polymer
take any two C atoms next to eachother and repalce C-C with C=C and get rid of the continuation bonds.
129
disposal of addition polymers
they are non-biodegradable due to the long time it takes to break down, and the strong covalent bonds that make them essentially inert at ordinary temperatures.
130
solution to disposal of addition piolymers
bury them in landfill sites.
| incinerate them
131
incinerating addition polymers
the large heat energy produced can be used for generating electricity but also contributes to global warming and release of toxic gases.
132
adv of addition polymers in landfill
no greenhouse gases or toxic gases produced
133
disadv of addition polymers in landfill
ugly, smelly and noisy, no one wants to live there.
uses large areas of land
the waste will be there for thousands of years
134
adv of addition polymers incinerated
requires little space
| can produce heat
135
disadv of addition polymers incinerated
expensive to build and maintain plant
produces greenhosue gases
releases toxic gases
the ash produced must still be disposed of in landfill sites
