Organics Flashcards
1
Q
what is a hydrocarbon
A
Hydrocarbon= a compound made of hydrogen and carbon atoms ONLY
2
Q
what is an Alkane
A
Alkane =a saturated hydrocarbon
3
Q
what is an alkene
A
Alkene = unsaturated hydrocarbon
4
Q
what is an empirical formula
A
Empirical Formula = the simplest whole number ratio of the atoms in a compound
5
Q
what is a molecular formula
A
Molecular Formula = the actual number of each type of atom in a molecule
The molecular formula is a multiple of the empirical formula
6
Q
what is a structural formula
A
Structural formula = shows how the atoms in a molecule are joined together
7
Q
what is a displayed formula
A
Displayed formula = (sometimes called full structural formula) displays EVERY single bond in the molecule
8
Q
what is a homologous series
A
Think of homologous series as families of organic compounds
Homologous series = a series of compounds with similar chemical properties because they have the same functional group
9
Q
what are some examples of homologous series
A
alkanes, alkenes, alcohol, carboxylic acids, esters
10
Q
what is the equations for alkanes and alkenes
A
General formula for:
1. alkanes = CnH2n+2
2. alkenes = CnH2n
11
Q
what are the prefixes for the alkanes/akenes, ie meth eth
A
Prefix for carbons 1-4
1 - Monkeys - Meth
2 - Eat - Eth
3 - Peanut - Prop
4 - Butter - But
Prefix for carbons 5-10 = shape name
5 - Pent
6 - Hex
7 - Hept
8 - Oct
9 - Non
10- Dec
12
Q
what is a functional grou[
A
Functional group = an atom/group of atoms that determine the chemical properties of a compound
13
Q
how to draw an organic compound (3)
A
To draw any organic compound:
1. Look at the prefix - draw the carbon skeleton
2. Look at the suffix - draw in the functional group
3. Fill in the H atoms - count as you fill - each C atom only makes 4 bonds
14
Q
what determines the prefix of a side branch
A
When there are branches, the amount of C atoms there are in the branch determines the prefix for that side branch
Side branch:
CH3 - methyl
CH2CH3 - ethyl
the branch name always comes at the start of the molecule name
15
Q
what are structural isomers
A
Structural isomers = different molecules that have the same molecular formula and different structural formula
16
Q
what are branched chain isomers
A
branched-chain isomers = think of a straight chain of carbons, with branches coming off of the MIDDLE carbons
If there are two branches of the same molecule, you put a ‘di’ in front - e.g. - dimethylpropene
17
Q
what 2 hydrocarbons cant have isomers
A
Ethene and propene can’t have any isomers
Alcohols = homologous series of compounds with an OH functional group attached to the hydrocarbon chain
18
Q
what is complete and incomplete combustion
A
Combustion = burning - it’s a reaction including oxygen
Complete combustion = when there is an excess of O2. Produced CO2 and H2O
Incomplete combustion = when there is insufficient amount of O2 - produces CO and H2O
19
Q
what is a substituion reaction
A
Substitution reaction = when an atom/group of atoms are replaced with different atom/group of atoms
ethane + bromine ⟶ bromoethane + hydrogen bromide
CH3CH3 + Br2 ⟶ CH3CH2Br + HBr
20
Q
what is an addition reaction
A
when an atom or group of atoms is added to a compound or substance
21
Q
what is crude oil
A
Crude oil = a mixture of hydrocarbons
Itis a finite, non-renewable resource
22
Q
how does crude oil form (4)
A
The formation of crude oil:
1. Millions of years ago plants and animals in the sea died and fell to the bottom
2. Over time, layers of sediment formed on top of them, burying them
3. Their shells and skeletons formed limestone
4. Under a lot of heat and high pressure from within the crust of the Earth, these limestone skeletons became crude oil
23
Q
what happens to he IMF when the hydrocarbon molecules get bigger
A
As the molecules become bigger, the intermolecular forces become stronger, because you have more of them with a bigger molecule
24
Q
what properties change as the hydrocarob molecules get bigger (4)
A
As the molecules get bigger:
The BP increases ⟶ the intermolecular forces grow stronger so more energy is required to overcome them as the molecule gets bigger
It becomes less volatile ⟶ as the intermolecular forces are stronger, the molecules are kept closer a lot easier, so it won’t turn into a gas very easily
It becomes more viscous ⟶ smaller molecules are more runny. bigger molecules means there is more attraction between the molecules as stronger intermolecular forces, so it will flow less
25
what is volatility
Volatility = the tendency to turn into a gas ⟶ it it is more volatile, it is more likely to turn into a gas at room temperature
26
what is viscosity
Viscosity = the thickness of a liquid ⟶ honey is more viscous than water
Crude oil is separated into its hydrocarbons using fractional distillation
27
what is a key feature of fractionaing column
The fractionating column has a negative temperature gradient ⟶ it is hot at the bottom, and gets colder as you go up
28
does temp go up when crude oil is vaporising (changing state)
When hydrocarbons within the crude oil and changing state, (vaporising), the temperature of the crude oil does NOT go up, as the energy put in is being used for the state change
29
what will be the first HCs that will vaporise in the frationating column
The first hydrocarbons to vapourise will be the shorter chain molecules, as they have lower BPs
30
what will happen to shorter chain HCs in the fractionating column and why
Once vaporised, the short chain hydrocarbon rises through the fractionating column, and will condense when it reaches its boiling point, which will be quite high up in the fractionating column, due to its low BP, and lower temperatures are found near the top due to the negative temperature gradient. Once it condenses, it will be collected in that fraction.
31
what will happen to longer chain HCs in the fractionating column and why
Once vaporised, the long chain hydrocaron will rise, staying relatively lower in the fractionating column, due to its high BP it will be fou d near the bottom due to the negative temperature gradient, once it condeses it will be collected in that lower fraction
32
what happens to the absolute shortest and longest HCs in the crude oil
The very short chain hydrocarbons do not condense, and the very long chain hydrocarbons do not vapourise in our fractionating column
So, the very short chain hydrocarbons, are collected at the top
The very long chain hydrocarbons remain at the bottom and are collected as residue
33
what are the longest HCs in the crude oil called which do not vaporise and uses
Part of this is a hydrocarbon called bitumen which is used in road making
34
what are the hydrocarbons in the fractions used for
These hydrocarbons from these different fractions are used as fuel
35
what is fuel
Fuel = something that releases energy when burnt
36
what are the shortest HCs in the crude oil called which do not condeses and uses
Refinery gases = a mixture of monkeys eat peanut butter - so a mixture of methane ethane propane butane
These gases can be separated if required, but are normally used as Liquefied Petroleum Gas (LPG) for heating and cooking in the home
37
whats similar about the HCs in the same fraction
The fractions collected from the distillation are mixtures of hydrocarbons with similar boiling points
So petrol is also a mixture of hydrocarbons with similar boiling points
38
what is petrol used for
Petrol is used as fuel for cars
39
what is kerosene used for
Kerosene is used as fuel for jet aircrafts, and as fuel for oil lamps in homes, and as paraffin for small heaters and lamps
40
what is diesel used for
Diesel = used as fuel for some cars, buses, lorries, railway engine
41
how can you get petrol from diesel
We can get petrol and other more useful organic molecules from diesel using a reaction called cracking
42
what is fuel oil used for
Fuel oil is used as fuel for ships and industrial heating
43
what is bitumin mixed with and why
Bitumen is mixed with small pieces of rock to make roads
44
what happens when we burn a lot of fossil fuels
When we burn fossil fuels from crude oil, we produce a lot of carbon dioxide
45
what are greenhouse gases
CO2 is a greenhouse gas
Greenhouse gases trap heat radiated from the Earth’s surface
46
what pH is normal rain and why
Normal rain is slightly acidic (around 5.6) as it has CO2 dissolved in it
47
how is acid rain formed (2)
Acid rain is formed when water and oxygen in the atmosphere either:
1. react with sulfur dioxide to produce sulfuric acid
2. react with oxides of nitrogen to produce nitric acid
48
where does sulfur dioxide and oxides nitrogen enter the atmosphere from (3)
Sulfur dioxide and oxides of nitrogen enter the atmosphere from power plants that burn fossil fuels, or from motor vehicles engines
Oxides of nitrogen has the formular NOx
Fossil fuels contain sulfur impurities
When we burn fossil fuels, these sulfur impurities also react with oxygen to form sulfur dioxide
49
give the equation for sulfur + oxygen
S(s) + O2 ---> SO2(g)
50
give the equation for sulfur dioxide to turn into sulfuric acid
Formation of acid rain:
2SO2 + 2H20 + O2 ⟶ 2H2S04
51
what is sulfurous acid and its equation
When sulfur dioxide dissolves in water a weaker acid, sulfurous acid is formed
SO2 + H2O ⟶ H2SO3
52
how does nitrogen react with oxygen in the air
In petrol engines, sparks are used to ignite the petrol-air mixture to power the car
So the engine gets very hot
So, this heat provides the activation energy required for the nitrogen and the oxygen in the air around the engine to react and combine
N2+O2--> 2NO
53
what are some problems with acid rain (3)
Problems with acid rain:
Kills trees and fishes in lakes
Some lakes become so acidic that it can’t support life at all
Limestone building, marble statues, and some metals like iron are attacked by acid rain
54
what is marble/ limestome
Marble/limestone = calcium carbonate
55
what are some ways to treat acid train (3)
Ways to treat acid rain:
Using catalaytic converters in engines can reduce the oxides of nitrogen formed
Remove sulfur impurities from fuel
‘Scrub’ the gases from power stations (ie lining the chimneys with calcium carbonate so it reacts with sulfer dioxide)
56
why are short HCs better than long chain HCs
From crude oil, short chain hydrocarbons are more profitable and more in demand
57
what is cracking
Cracking = a process converting long-chain alkanes into shorter chain alkanes and alkenes
Alkenes are made in cracking
58
how does cracking happen (2)
Cracking:
1. Long chain hydrocarbons (like fuel oil) is first vapourised and then is passed over catalysts called silica and alumina (silicon dioxide and aluminium oxide), at very high temperatures of 600 degrees
2.
Using the catalyst allows for this reaction to happen at 600 degrees - cracking can be done without a catalyst, just at a much higher temperature
59
what type of reaction is cracking
thermal decomposition
60
Two important reasons for cracking:
1. to produce more short chain/useful hydrocarbons like petrol
2. to produce alkenes, which we use to make a lot of polymers like plastics
61
what must be done after cracking the long HCs into shorter HCs
At the end of cracking, you are left with a very complex mixture of smaller chain hydrocarbons which then need to be processed with more fractional distillation
62
what is silica
a catalyst silicon dioxide
63
what is alumina
a cataylyst aluminum oxide
64
why do homologous molecules ave similar chemical properties
the molecules in a homologous series have similar chemical properties as they have the same functional group
they also show a trend in physical properties (steady increase in mass, boiling point etc)
65
are alkanes reactive
Alkanes are quite inert (inert = unreactive), as they are saturated with strong bonds
66
what OTHER substance can be produced in incompelte combustion
In incomplete combustion, soot can be produced as well which is pure carbon, so if the question mention soot being formed, you just do + C (of course balance as necessary)
67
in what conditions do alkanes react with halogens and what reaction would it be (2)
Alkanes react with halogens in UV light (so this can take place in sunlight)
This would be a substitution reaction, where a Hydrogen atom in the alkane is substituted with a halogen atom
68
Mono-substitution =
only one H atom in alkane is replaced by a halogen atom
69
what state are the first 4 carbons of alkanes /alkenes
Alkanes and alkenes are both gases at room temperature for the first 4 carbons
70
what HC can undergo addition reactions and why
Alkenes can undergo addition reactions, as the double bond can be broken to create two new bonds
71
what happens when a halogen is added to an alkene
When adding a halogen to an alkene in an addition reaction, both halogen atoms are added to the molecule
An example of a product would be 1,2-dibromoethane
72
what is the test for alkenes
Test for alkenes - alkenes in bromine water (liquid bromine) ⟶ if it is an alkene, the solution changes from an orange-brown colour to colourless
73
what is a hydration reaction
A hydration reaction = adding a water molecule to an alkene
74
how to make an alchohol from an alkene and what are the conditions
Alkene + water(g) ⟶ alcohol
Conditions: 300degrees, high pressure, and a phosphoric acid catalyst
75
how do you name alchohols
With naming alcohols, you put a number before the -ol, for where the functional group goes
Ex: propan-1-ol, propan-2-ol
76
what is ethanol fuel wise
Ethanol is a biofuel (fuel made from biological sources)
sugarcane and corn are other examples of biofuel
77
what is ethanoic acid commonly known as
Ethanoic acid = vinegar
78
what happens when alchohol is exposed to the air for a long time
If alcohol/ethanol is exposed to the air for a long time, it can become oxidised by microorganisms in the air like bacteria and yeast to form ethanoic acid
79
what is the test for alchohols (2)
A few drops of ethanol are added to an ORANGE mixture of potassium dichromate and dilute sulfuric acid
This is heated in a water bath in a test tube
The orange solution changes to a green colour if ethanol is present - the presence of ethanoic acid, reduces the potassium dichromate, which turns the solution green
80
how can alchohol be made other than hydration
Alcohol can be made from the fermentation of yeast
81
describe fermentation (4)
Process of fermentation:
1. Yeast is added to a sugar/starch solution and left in warm anaerobic conditions
Enzymes in the yeast convert the sugar into ethanol and CO2
It is important to store the yeast around 30degrees, no more than 40, as the enzymes would denature
At a much lower temperature, the reaction will be too slow
82
why cant you make pure alchohol from fermentation
You can’t make pure alcohol by fermentation as with more than 15% alcohol, yeast is killed
83
how is alchohol purified after fermentation
Alcohol made from fermentation is purified by fractional distillation, which uses the different boiling points of ethanol and water
water - 100 degrees
ethanol - 78 degrees
84
what is the boiling point for water
water - 100 degrees
85
what is the boiling point for ethanol
ethanol - 78 degrees
86
what are the comparison points between hydration and fermentation for making alchohols (5)
Comparison points for making ethanol from fermentation vs hydration of ethene:
1. use of resources
2. type of process
3. rate of reaction
4. quality of product
5. reaction conditions
1. Resources - F uses renewable resources, H uses finite, non-renewable resources
2. Type of process - F is a batch process - needs to be done in batches which is inefficient, but H is a continuous flow process which is more efficient
3. Rate of reaction - F is slow (days), H is quick
4. Quality of product - F impure ethanol which needs further processing, H much purer ethanol
5. Reaction conditions - F - gentle temperatures and pressures, H- uses high temperatures and pressures, which uses energy to create
Vinegar is diluted ethanoic acid, not pure
Carboxylic acids are formed by the oxidation of the alcohol
The functional group of carboxylic acids is -COOH,
Carboxylic acids are weak acids
Weak dilute acids react the same as any acid - with a metal it produces salt + H2
Ethanoic acid as an ion is CH3COO^1- (it’s just ethanoic acid without the last H) - you need to use the fact that it has a 1- charge to do drop and swap to work out the correct formulae
87
compare the use of resources when making alchohol with fermentatio or hydration
1. Resources - F uses renewable resources, H uses finite, non-renewable resources
88
compare the types of processes used when making alchohol with fermentatio or hydration
2. Type of process - F is a batch process - needs to be done in batches which is inefficient, but H is a continuous flow process which is more efficient
89
compare rate of reaction when making alchohol with fermentation or hydration
3. Rate of reaction - F is slow (days), H is quick due to cataluyst HPO3
90
compare the quality of the product when making alchohol with fermentatio or hydration
4. Quality of product - F impure ethanol which needs further processing, H much purer ethanol
91
compare the reaction conditions /expensiveness when making alchohol with fermentation or hydration
5. Reaction conditions - F - gentle temperatures and pressures, H- uses high temperatures and pressures, which uses energy to create
92
is vinergar pure ethanoic acid
Vinegar is diluted ethanoic acid, not pure
93
how are carboxylic acids formed
Carboxylic acids are formed by the oxidation of the alcohol
94
what is the functional group of carboxylic acids
The functional group of carboxylic acids is -COOH,
95
how strong are carboxylic acids
Carboxylic acids are weak acids
96
what happens when ethanoic acid reacts with a metal
Weak dilute acids react the same as any acid - with a metal it produces salt + H2
Ethanoic acid as an ion is CH3COO^1- (it’s just ethanoic acid without the last H) - you need to use the fact that it has a 1- charge to do drop and swap to work out the correct formulae
97
what is a saturated hydrocarbon
has no double bonds only single
98
how are esters formed
Esters are formed by a reaction between alcohol and carboxylic acid
99
what is the functional group of esters
The functional group is -COO
100
what reaction are esters made in
Esters are made in a condensation reaction
Condensation reaction = a water molecule is formed
101
what are the conditions for esterification
Conditions: requires heat, and a concentrated sulfuric acid catalyst
This condensation reaction is esterification
This is a reversible reaction
102
how to name esters
When naming esters, the alcohol comes first, when drawing esters, the carboxylic acid comes first (c is easier to draw, so you start with carboxylic acid when drawing)
Name alcohol-yl acid-anoate ⟶ methyl propanoate, ethyl pentanoate
103
what are small esters and normal esters used in
Small esters are used in solvents, but most esters are used in food flavourings and perfumes
104
properties of esters (2)
Esters are very volatile liquids with distinctive smeels
105
what is polymerisation
polymeration to form addition polymers
Polymerisation = the joining up of lots of little molecules called monomers to make one big molecule calaled a polymer
lots of ethene forms POLYethene
106
what is addition polymerisation
Addition polymerisation = molecules simply add on to each other without anything else being formed
107
how to draw a repeating unit of a polymer
the displayed formula with the trailing bonds on each side
108
how to draw a polymer
the structural formula with the trailing bonds and brackets on each side, the trailing bonds will trailing over the brackets, overlapping, and outside the brackets on the right bottom side u will have "n" , so 5 ethene molecules u will write 5
109
does a polymer decolourise bromine water like alkenes
A polymer does not decolourise bromine water, as there are no longer any double bonds
110
what are the 2 types of polyethene
Two types of polythene: Low-density polyethene (LDPE) and high density polythene (HDPE)
111
what is lowdesity polyethene used for
Low-density polyethene is flexible and not very strong ⟶ used to make polythene bags
112
what is high desnity polyethene used for
High density polyethene is quite strong and rigid ⟶ used to make plastic bottles, such as milk bottles
113
what is polypropene used for
Polypropene is stronger than polyethene - used to make ropes and crates
- Seen as PP next to a recycling symbol
114
what is polychloroethen used for (2)
Polychloroethene = used to be called PVC
Polychloroethene = quite strong and rigid ⟶ used for water pipes or replacement windows
Can be made flexible by adding plasticisers, which then allows it to be used for sheet floor covering, or clothes, or electrical insulation
115
what is polytetrafluoroethen used for, tetra means 4 not 3 (2)
Polytetrafluoroethene (PTFE) = this is Teflon ⟶ used as a non-stick coating for pots and pans ⟶ very unreactive as the carbon-fluorine bonds are very strong
As I is unreactive, it is also used to line containers that store corrosive chemicals
116
what is a bad way of disposing of plastics
Addition polymers (thinking about plastics)
One way to dispose of addition polymers is landfill sites - this is really bad, as they are non-biodegradable as they are inert due to their strong covalent bonds
117
what does biodegradable mean
Biodegradable = can’t be broken down by bacteria in the environment
118
why is recycling important
It’s important that we recycle plastics to save raw materials and as they won’t break down for a long time
119
why is burning of plastics bad
Some countries burn plastics, but this uses a lot of energy, and leads to a lot of carbon emissions
120
advantages of landfill sites (2)
Advantages of landfill sites for disposal:
1. No carbon emissions/greenhouse gases or toxic gases emitted into the atmosphere
2. Cheap
121
disadvantages of landfill sites (3)
Disadvantages:
1. Visual pollution (not very pleasant to look at), smelly
2. Uses large areas of land
3. The waste will remain there for thousands of years
122
advantages of burning plastics (2)
Advantages of burning/incineration
1. Does not need a lot of space
2. Can produce heat for local homes or be used to produce electricity
123
disadvantages of burning plastics (2)
Disadvantages:
Expensive to build and maintain the plant
Produces greenhouse gases and toxic gases
Produces ash that still needs to be disposed of (maybe in landill sites)
124
what is condensation polymerisation
Condensation polymerisation = when monomers join to make a polymer, a small molecule such as H2O or HCl comes out
125
what is the monomer in addition polymers
In addition polymers, the monomer is ethene
126
what is the monomer for condensation polymers
In condensation polymers, the monomer is ester
127
what is a diol and how to write
A diol is a molecule that has two alcohol functional groups - diols can be monomers
Diols have an extra ‘e’ in them compared to alcohol - so its not ethanOL, it’s ethanEdiol
128
what are di carboxylic acids
There are also dicarboxylic acids ⟶ molecules that have the carboxylic acid functional groups attached to each end
129
can diol and di carboxylic acids be used in condensation polymers
Both of these molecules can be used as monomers for condensation polymers
130
which are more reactive, addition or condensation polymers
Compared to addition polymers, condensation polymers are more reactive as the ester linkage will all break down eventually ⟶ so biodegradable polyesters that can break down faster have been produced
131
