Topic 7- Hydrocarbons and Crude Oil and organic compounds Flashcards
(116 cards)
1
Q
What is organic chemistry?
A
Organic chemistry is the study of substances that contain carbon atoms.
2
Q
Why is this branch of chemistry known as Organic Chemistry?
A
All living things are made up from carbon compounds, and so this branch of chemistry was historically known as organic chemistry (organic = made from plants and animals).
The main source of organic compounds are living, or once or once living materials from plants and animals. However it has been discovered that these carbon compounds could also be made in the lab from non-living materials-chemicals.
3
Q
Name one source of carbon compounds
A
These sources include fossil fuels which are a major source of feedstock (fuel) for the petrochemical industry.
Unrefined crude oil is a fossil fuel often used.
4
Q
Why is the study and practice of organic chemistry important?
A
Because chemists are able to take organic molecules and modify them in many ways to make new and useful materials such as polymers, perfumes, flavourings, dyes, detergents and medicines.
5
Q
Where is crude oil found?
A
Crude oil is a finite resource found under the ground in rocks.
6
Q
What is crude oil made from?
A
Crude oil is the remains of dead plants and animals mainly consisting mainly of plankton that was buried in mud.
7
Q
What is the structure of crude oil?
A
Crude oil is a mixture of a very large number of compounds. Most of the compounds in crude oil are hydro carbons.
8
Q
What is a hydrocarbon?
A
A hydrocarbon is any molecule that contains hydrogen and carbon atoms only. So C10 H22 (decade, an alkane) is a hydrocarbon, but CH3 COOC3 H7 (an ester) is not- it contains oxygen.
9
Q
How are hydrocarbons structured?
A
Each carbon atom must have 4 covalent bonds and each hydrogen must have 1 covalent bond.Image result for hydrocarbon methane structure
10
Q
What are most of the hydrocarbons in crude oil called?
A
Most of the hydrocarbons in crude oil are called alkanes.
11
Q
What are alkanes?
A
1) Alkanes are the simplest type of Hydrocarbon you can get. They have the general formula Cn H2n+2.
2) The alkanes are a homologous series:
- A group of organic compounds that share a general formula.
- Have similar chemical properties, so react in a similar way.
3) Alkanes are saturated compounds- each carbon atom forms four single covalent bonds.
12
Q
What is a homologous series?
A
In organic chemistry, a homologous series is a series of compounds with the same general formula.
A homologous series is a family of hydrocarbons with similar chemical properties so react similarly.
13
Q
What does saturated mean?
A
In organic chemistry, a saturated compound is a chemical compound that has a chain of carbon atoms linked together by single bonds. Saturated hydrocarbons are called alkanes.
14
Q
What are the first four alkanes called?
A
1) Methane
2) Ethane
3) Propane
4) Butane
15
Q
How can alkane molecules be represented?
A
Alkane molecules can be shown:
- Using their molecular formula
- Displayed formula (a drawing showing all the atoms and bonds in a molecule)
16
Q
What affects the properties of hydrocarbons? And what 3 things does this effect?
A
The more carbon atoms a hydrocarbon molecule has, the longer, larger and heavier it will be. This will affect its physical properties:
- Boiling Point. Longer molecules have a higher boiling point because they are heavier, move more slowly, become tangled, have greater intermolecular forces and therefore require more heat energy to gain enough speed/energy to leave the surface of the liquid to become a gas, i.e. boil/evaporate.
- Flammability. Smaller (weaker) molecules burn more easily e.g. methane, butane or octane. Larger molecules do not tend tend to burn, e.g bitumen-you can’t easily set fire to the road! Therefore, the smaller hydrocarbons tend to be used as fuels.
*Viscosity (thickness): Longer molecules become more tangled, possess greater intermolecular forces and are less able to move past each other-compare octane (8 carbons clumped together like pasta) and bitumen (120 carbons tangled like spaghetti).
The shorter the molecules, the more runny the hydro carbon is- that is, the less viscous it is.
17
Q
What is fractional distillation?
A
Fractional distillation is a technique used to separate hydrocarbons into fractions, each of which contains molecules with a similar number of carbon atoms.
Fractions being the individual hydrocarbons, distillation being the process of purifying a substance via heating and cooling.
18
Q
Why is fractional distillation an important technique?
A
As a mixture, crude oil is not useful, but if we separate it into fractions i.e. groups of hydrocarbons of similar size, from the smallest to the largest, we have a very useful collection of molecules, which can be further processed to produce FUELS for cars, lorries etc and FEEDSTOCK for the PETROCHEMICAL INDUSTRY, and to make medicines, plastics, etc.
19
Q
How does separation of hydrocarbons occur? (Do not learn this, just understand)
A
1) The oil is heated until most of it has turned into gas. the gases enter a fractionating column (and the liquid bit is drained off).
2) In the column there is a temperature gradient ( it’s hot at the bottom and cooler as you go up).
3) The longer hydrocarbons have high boiling points. They condense back into liquids and drain out of the column early on, when they’re near the bottom. The shorter hydrocarbons have lower boiling points. They condense and drain out much later on, near to the top of the column where it’s cooler.
4) You end up with the crude oil mixture separated out into different fractions. Each fraction contains a mixture of hydrocarbons that all contain a similar number of carbon atoms, so have similar boiling points.
20
Q
Explain the process of fractional distillation. (previous exam question, LEARN!)
A
The crude oil is HEATED to EVAPORATE hydrocarbons to vapour. The different hydrocarbons COOL and CONDENSE at different temperatures because they have different boiling/condensation points. This is because there is a TEMPERATURE GRADIENT in the chamber.
In summary:
- Crude oil is heated
- to evaporate hydrocarbons
- there is a temperature gradient in the chamber
- so fractions condense
- at different levels
21
Q
What fuels are produced from crude oil?
A
Many of the fuels on which we depend for our modern lifestyle, such as petrol, diesel oil, kerosene, heavy fuel oil and liquefield petroleum gases, are produced from crude oil.
22
Q
What useful materials on which modern life depends are produced by the petrochemical industry?
A
-Solvents -Lubricants -Polymers -Detergents
23
Q
How are there so many natural and synthetic carbon compounds?
A
The vast amounts of carbon compounds is due to the ability of carbon atoms to bond together to form different groups called homologous series.
Alkanes, alkenes, as well as other families such as alcohols and carboxylic acids, are all examples of different homologous series.
24
Q
What is complete combustion?
A
Hydrocarbons contain H and C atoms. When complete combustion occurs, the hydrogen is oxidised(combined with oxygen) to form water, H2O and the carbon is oxidised to form carbon dioxide, CO2. Energy in the form of heat and light is released.
25
What is the equation for complete combustion of a hydrocarbon?
hydrocarbon + oxygen -------> carbon dioxide + water vapour
26
What is an Alkene?
What is the general formula of an alkene?
1) Alkenes are HYDROCARBONS with a DOUBLE COVALENT BOND between two of the CARBON atoms in their chain.
2) The C=C double bond means that alkenes have two fewer hydrogens compared with alkanes. This makes them UNSATURATED.
3) The C=C double bond can open up to make a SINGLE BOND, allowing the two carbon atoms to bond with OTHER ATOMS. This makes alkenes REACTIVE - far more than reactive than other ALKANES.
4) The first 4 alkenes are ethene (2 carbon atoms), propene (3 Cs), butene (4 Cs) and pentene (5Cs).
- Like alkanes, they form a homologous series, each differing by a CH2 unit. They have a general formula C2H2n.
N.B. There is no such thing as methene- because it cannot contain a double bond.
27
How reactive are alkenes with bromine water?
| Do alkenes react with other alkenes?
Alkenes are more reactive than alkanes, reacting with bromine to make a colourless bromine water.
Alkenes can also react with other alkenes to make polymers (plastics). Alkenes are also useful starting materials for other chemicals and medicines.
28
How reactive are alkanes with bromine water?
Why is the bromine water test used?
Alkanes are very un-reactive and will not make the bromine water colourless.
The bromine test is used to distinguish alkanes from alkenes. ALKENES DECOLOURISE BROMINE WATER.
29
Which hydrocarbon fractions are in greatest demand?
The fractions containing smaller hydrocarbons tend to be used as fuels (e.g. heptane, C7H16, is a major component of gasoline/petrol), whilst the larger hydrocarbons are used for surfacing roads (e.g. bitumen, C120H242).
The global DEMAND for FUEL is HIGH, meaning that there is a shortage of SHORT HYDROCARBONS and an excess of long/large hydrocarbons. The solution to the problem is to convert large molecules into smaller molecules.
30
What is cracking?
- SHORT-CHAIN HYDROCARBONS are flammable so make good fuels and are in HIGH DEMAND. LONG-CHAIN hydrocarbons form thick gloopy liquids like TAR which aren't all that useful, so...
- A lot of the LONGER alkane molecules produced from fractional distillation are SPLIT and turned into smaller, more USEFUL ones by a process called CRACKING.
So cracking is a thermal decomposition reaction because large alkanes are heated to a vapour and broken up (decomposed) into smaller molecules.
31
What products are formed during the process of cracking?
DURING CRACKING A MIXTURE OF ALKANES AND ALKENES IS ALWAYS MADE. Some of the products of cracking are useful as fuels, e.g. petrol for cars and paraffin as jet fuels
32
What is the use of Alkenes?
Alkenes are used to produce polymers and as starting materials for the production of many other chemicals.
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What are the different methods of cracking?
*Cracking is a thermal decomposition reaction-breaking molecules down by heating them.
* There are two methods of cracking:
- Catalytic cracking (A)
- Steam cracking(B)
A
1)For catalytic cracking the first step is to heat long-chain hydrocarbons at very hight temperatures to vaporise them (turn them into gas). In industry this would take place in a cracking unit next to a fractional distillation column.
2) Then the vapour is passed over a hot powered aluminium oxide catalyst.
3) The long-chain molecules split apart on the surface of the specks of catalyst.
In the laboratory, a much simpler set up is more usual. The porcelain chips act as a catalyst. The alkane used here is a paraffin, each molecule containing approximately 20 carbons
B
You can also crack hydrocarbons if you vaporise them, mix them with steam and then heat them to a very high temperature. This is known s steam cracking.
34
What is a functional group?
A functional group is an atom or atoms that is responsible for most of the chemical reactions of an organic compound.
35
What is the functional group of alkenes?
All alkenes have the functional group C=C, so they all react in similar ways. So you can suggest the products of a reaction based on your knowledge of how alkenes react in general.
36
Are alkenes a homologous series?
Yes, because they have the same functional group and react in similar ways.
37
How do alkenes react?
Most of the time alkenes react via ADDITION REACTIONS. The carbon double bond C=C will open up to leave a SINGLE BOND and a new atom is added to each carbon.
38
How do alkenes react with oxygen?
1) Alkenes can react with a large amount of oxygen in COMBUSTION (burning) reactions, just like alkanes. When a large amount of oxygen is present they COMBUST COMPLETELY to produce only water and carbon dioxide.
2) However we do not generally combos alkenes as there isn't enough oxygen in the air for this, so when you burn them they tend to undergo INCOMPLETE COMBUSTION.
3) We don't combust alkenes for 2 reasons:
- when combusted carbon dioxide and water are still produced, but you can also get carbon and monoxide (carbon produces soot).
alkene+oxygen=carbon +carbon monoxide +CO2+H2O
-Incomplete combustion results in a smoky yellow flame, and less energy being released compared to complete combustion of the same compound.
39
How do alkenes react with hydrogen?
- Alkenes are unsaturated i.e. not yet full up with hydrogen atoms-there is space to add more at the C=C double bond. Alkanes, oppositely are known as saturated (full up) as they can't fit more hydrogens onto their single bonds. When hydrogen is added to an unsaturated alkene, a saturated alkene is made.
- The reaction is called a hydrogenation (hydrogen is added).
- Occurs at 150 degrees celsius.
- A nickel catalyst must be present.
40
How do alkenes react with halogens?
1) Alkenes will also react in ADDITION REACTIONS with HALOGENS such as bromine, chlorine and iodine.
The molecules formed are saturated, with C=C carbons each becoming bonded to a halogen.
2)For example, bromine and ethene react together to form dibromoethane: There are two bromine atoms so it's called DIbromoethane.
Remember the addition of bromine to a double bond can be used to test for alkenes:
1) When orange BROMINE WATER is added to a SATURATED COMPOUND, like an ALKANE, no reaction will happen and it'll stay BRIGHT ORANGE.
2) If it's added to an ALKENE the BROMINE will add across the double bond making a COLOURLESS dibromo-compound-so the bromine water is decolourised.
41
How do alkenes react with water (steam)?
- Alkenes react with STEAM by an addition reaction whereby OH and H of water are added across the C=C double bond and an ALCOHOL is produced.
- It is called a hydration action.
- HIGH TEMPERATURES and HIGH PRESSURES are required, in addition to a CONCENTRATED PHOSPHORIC ACID CATALYST.
42
What are alcohols?
The alcohols are a group of compounds that make up an homologous series all containing the functional group -OH.
It follows an homologous series whereby each member differs from its neighbour by a CH2 unit.
43
What is the general formula of an alcohol?
The general formula for an alcohol is CnH2n+1OH. So an alcohol with two carbons has the formula C2H5OH.
44
What is the naming system of alcohols?
The basic naming system of alcohols is the same for alkanes-but you replace the final 'e' with 'ol'.
45
What are the names of the first 4 alcohols?
1) Methanol (1 carbon)
2) Ethanol (2 Cs)
3) Propanol (3 Cs)
4) Butanol (4Cs)
46
What are the properties of alcohols?
- The first four alcohols have similar properties.
- Alcohols are FLAMMABLE. They undergo complete combustion in air to produce CARBON DIOXIDE and WATER.
- Methanol, ethanol, propanol and butanol are all soluble in water. Their solutions have a NEUTRAL pH.
- They also react with SODIUM. One of the products of this reaction is HYDROGEN.
- ALCOHOLS can be OXIDISED by reacting with oxygen (e.g. from the air) to produce a CARBOXYLIC ACID.
- Different alcohols form different carboxylic acids. For example, METHANOL is oxidised to METHANOIC ACID, while ethanol is oxidised to ethnic acid.
47
What are the uses of alcohols?
1) Alcoholic drinks- Ethanol is the main alcohol in alcoholic drinks. It's not as toxic as methanol (which causes blindness if drunk) but it still damages the liver and brain.
2) Alcohols such as methanol and ethanol are used as solvents in industry. This is because they can dissolve substances that WATER CAN'T DISSOLVE-e.g. hydrocarbons, oils and fats. They are often used to dissolve perfume molecules and medicines (that aren't soluble in water).
3) The first four alcohols are used as fuels. For example ethanol is used as a fuel in spirit burners-it burns fairly cleanly and it's non-smelly.
48
How is ethanol made using sugars?
| students should know the CONDITIONS used for the FERMENTATION OF SUGAR USING YEAST
Ethanol is the alcohol found in alcoholic drinks such as wine or beer.
1) FERMENTATION uses an enzyme in the east to convert sugars into ethanol. Carbon dioxide is also produced. The reaction occurs in solution so the ethanol produced is aqueous.
Sugar----------> ethanol + carbon dioxide
yeast
2) Fermentation happens fastest at a temperature of around 37 degrees celsius, in a SLIGHTLY ACIDIC solution and under ANAEROBIC CONDITIONS (no oxygen).
3) under these conditions the enzymes in yeast works best to convert the sugar to alcohol. If the conditions were different, for example a LOWER PH/HIGHER TEMPERATURE or HIGHER PH/ LOWER TEMPERATURE the enzyme could be denatured (destroyed) or could work at a much slower rate.
So AQUEOUS SOLUTIONS OF ETHANOL ARE PRODUCED WHEN SUGAR SOLUTIONS ARE FERMENTED USING YEAST.
Conditions: YEAST, NO OXYGEN, APPROXIMATELY ROOM TEMPERATURE.
49
How do alcohols react with water?
Alcohols possess covalent bonds that do not break easily so DO NOT REACT WITH WATER other than to dissolve easily in it (e.g. ethanol is dissolved in vodka, wine etc). The solution formed is neutral. The only thing that has changed is that it is aqueous.
50
How do alcohols react with oxygen (combustion)?
All alcohols burn in air: Indeed methanol mixed with ethanol (methylated spirits is often used as fuel when camping, and ethanol is mixed with petrol in places like Brazil as it burns well in car engines. CO2 and H2O are produced.
51
What is oxidisation?
Oxidation is the gain of oxygen by a substance. For example, magnesium is oxidised when it reacts with oxygen to form magnesium oxide:
magnesium + oxygen → magnesium oxide
2Mg + O2→ 2MgO
52
How do alcohols react with oxygen (mild oxidation)?
| NEW TO SPEC- LEARN!!!
In combustion, alcohols molecules are blasted apart vigorously to form CO2 and H2O. However, a mild oxidising agent will gently add oxygen (or remove hydrogen) from a molecule without breaking it apart. Oxidising agents can be chemicals such as O2 in the air, or biological in origin such as some microbes. When alcohols are oxidised they produce carboxylic acids. The most common example is when wine containing ethanol is oxidised by the air to make vinegar (ethnic acid).
53
How do alcohols react with sodium metal?
Sodium metal will react with alcohols in a similar way to when sodium reacts with water, producing hydrogen gas and a basic solution.
54
What are carboxylic acids?
- The CARBOXYLIC ACIDS are a group of compounds that all contain a -COOH functional group. The -COOH group consists of a carbon atom that has formed a DOUBLE BOND with a lone oxygen atom and a single bond with an oxygen atom in an -OH group.
- Carboxylic acids follow an homologous series whereby each member differs from its neighbour by a CH2 unit.
55
How do you correctly write out the chemical formula of a carboxylic acid?
When you're giving the chemical formula of a carboxylic acid, it;s crucial that you show the -COOH clearly. As a result the chemical formulas of carboxylic acids are usually written out in full.
Example:
You would always give the chemical formula of ethnic acid as CH3COOH. You would't just give it as C2H4O2, because then you wouldn't be able too see the -COOH functional group.
56
How can you identify a carboxylic acid?
To identify wether a compound is a carboxylic acid or not, just look out for a -COOH group or 'anoic' at the end of its name.
57
How do carboxylic acids react with water?
- Carboxylic acids DISSOLVE EASILY IN WATER just like alcohols (e.g. table vinegar is 5% ethnic acid dissolves in 95% water).
- Unlike alcohols the CARBOXYLIC ACID HAS A PARTIALLY IONIC O-H BOND which will PARTIALLY react with water by PARTIALLY DISSOCIATING (breaking up) to form a carboxylate ion (containing -COO).
This dissociation processes called ionisation because ions are made. It results in the production of aqueous H+ ions, making the solution acidic.
-However because they only partially ionise in water only some H+ ions are made, so are WEAK ACIDS with a pH of only about 4. As a result, carboxylic acids have a HIGHER pH (are less acidic) .
This is why we can eat vinegar without corrosion.
58
How do carboxylic acids react with carbonates?
They react with other acids such as carbonates to produce a salt and water. The salts formed end in 'anoate'. For example, methanoic acid will form methanoate.
Example:
Ethnic acid reacts with sodium carbonate to form carbon dioxide, water and a salt called sodium ethanoate. Here's the equation:
ethanoic + sodium ---------> carbon + sodium + water
acid carbonate dioxide ethanoate
59
How do carboxylic acids react with alcohols?
-Carboxylic acids and alcohols can be reacted together if a SMALL AMOUNT OF CONCENTRATED H2SO4 (sulfuric acid) is present as a CATALYST. In effect, a molecule of water is removed from the carboxylic acid and alcohol and the remaining fragments combined together. The conc of H2SO4 is able to catalyse the reaction because it absorbs water strongly, encouraging the reaction to proceed. The organic products are termed ESTERS and contain the ester functional group -COO.
60
Summaries what an ester is and how it is formed...
1) Esters have the functional group -COO.
2) Esters are formed from an ALCOHOL and a CARBOXYLIC ACID.
3) An ACID CATALYST is usually use e.g. concentrated sulphuric acid H2SO4.
61
What is the formula to make an ester?
acid catalyst
| alcohol + carboxylic acid --------------------> ester + water
62
What are the first 4 carboxylic acids called?
1) Methanol acid
2) Ethnic acid
3) Propanoic acid
4) Butanoic acid
63
What is the only ester you need to learn for the exam called?
It's formed from ethanol and ethanoic acid.
The one you need to make sure you know is
ETHYL ETHANOATE-the examiners could ask you about this one, so learn where the functional group is -COO.
ethanol + ethanoic acid ͢ Ethyl ethanoate + water
64
What does poly mean?
Poly = many
65
What does mono mean?
Mono = one
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What does mer mean?
Mer = part
67
What is a monomer?
A small molecule that can be joined together with other small molecules to form a polymer.
68
What is a polymer?
A polymer is a LONG chain MOLECULE that is formed by joining lots of smaller molecules (monomers).
So MONOMERS JOIN together to form POLYMERS.
69
How many monomers are polymers in science and nature made from?
Polymers in science and nature are made from hundreds, even thousands of monomer units.
70
How are a variety of polymers made?
Different types of polymer are made from different types of monomer.
71
What are the four types of monomer we learn called?
1. Alkenes
2. Alcohol and Carboxylic acid combinations
3. Amino acids
4. Nucleotides
72
What type of polymer is made from alkene monomers?
What are the uses of the polymers created from alkene?
Type of polymer made:
-Addition polymer
Uses of polymer:
- Addition polymers are used in plastic bags, plastic chairs, non-stick coatings on kitchenware etc.
73
What type of polymer is made from Alcohol and Carboxylic acid combinations monomers?
What are the uses of the polymers created from Alcohol and Carboxylic acid combinations?
Type of polymer made:
- (manufactured) condensation polymer
Uses of polymer:
- Nylon and polyester clothing, Kevlar armoured jackets
74
What type of polymer is made from amino acid monomers?
What are the uses of the polymers created from amino acids?
Type of polymer made:
-Proteins
Uses of polymer:
-Growth and repair of living things, enzymes, muscles etc.
75
What type of polymer is made from nucleotides?
What are the uses of the polymers created from nucleotides?
Type of polymer made:
- DNA
Uses of polymer:
-Defines the characteristics of all living things.
76
How are polymers synthesised (made)?
Polymers can either be synthesised (made) in industry to produce objects, or they can be biological polymers such as proteins and DNA, which are constructed inside the living cell.
77
Define addition polymer?
A large molecule made from alkene monomers which bond together by opening up their double bonds and forming long chains.
78
Explain how addition polymer are formed.
The small, unsaturated alkene monomers have double bonds which open up and attach to other monomers that are also opening up. The result is a long, saturated alkane chain containing only single bonds. This is called ADDITION POLYMERISATION because many polymers are being added to make the polymer.
79
How do you represent monomers and polymers?
N.b.In addition polymers the repeating unit has the same atoms as the monomer because no other molecule is formed in the reaction.
We can abbreviate long repeating molecules by identifying the repeating unit, and using brackets around it with the letter n, which represents the number of monomers used.
80
Define condensation polymer.
A large molecule made from monomers with at least two different functional groups that react together to form chains. A small molecule is lost for each bond formed.
81
Describe what is meant by a condensation polymer.
Condensation polymers are also made from MONOMERS.
In condensation polymers, the monomers are not ALKENES.
When these monomers react, we lose SMALL MOLECULES such as WATER.
82
Describe how condensation polymers are formed.
- With condensation polymers, we start with TWO DIFFERENT MONOMERS.
- Each monomer has two of the same FUNCTIONAL GROUPS.
Example (the functional groups are in lower case)
ho-CH2-CH2-oh
and
hooc-CH2-CH2-CH2-CH2-cooh
- To form the condensation polymer, we REACT our two monomers together.
- The functional groups join at each end of the molecule by forming BONDS.
- The monomers in the example react to form an ester and water.
- We can now continue to ADD MONOMERS to either end.
This allows us to produce a LONG polymer.
Water molecules are also produced.
83
Why is the process called condensation polymerisation?
When monomers react together, bonds form between them, making polymer chains.
For EACH NEW BOND that forms, a SMALL MOLECULE (for example water) is LOST.
This is why its called CONDENSATION polymerisation.
84
What are the simplest type of condensation polymers?
The simplest type of condensation polymers contain two different monomers, each with two of the same functional group.
85
What are diols and dicarboxylic acids?
Diols and dicarboxylic acids are molecules containing two alcohol or two carboxylic groups respectively.
86
What link is formed when dicarboxylic acids react with diols?
Dicarboxylic acids react with diols to form ESTER LINKS- this is a condensation reaction.
87
What is a polyester?
Esters can be made into very long chains which contain thousands of esters joined together. These are called polyesters (‘poly’ means ‘many’).
88
How are polyesters formed?
Dicarboxylic acids can react with diols to form ESTER LINKS- this is a condensation polymer.
The molecule with the ester link has a functional group at each end.
These can also react in condensation reactions, making the chain longer.
The series of reactions together is known as condensation polymerisation and the resultant polymer is called a POLYESTER.
89
Differences between additional and condensation polymerisation...
How many monomer types are in each polymer?
Addition- In addition polymerisation there is only one monomer type containing a C=C bond.
Condensation: either
-Two monomer types containing two of the same functional groups.
or
-One monomer type with two different functional groups.
90
Differences between additional and condensation polymerisation...
How many products are formed?
Addition polymerisation: Only one product formed- the polymer.
Condensation polymerisation: Two types of product- the polymer and a small molecule (e.g. water).
91
Differences between additional and condensation polymerisation...
What functional groups are involved in addition and condensation polymerisation?
Addition Polymerisation:
The only functional group involved is the carbon-carbon double bond in the monomer.
Condensation polymer:
Involves two reactive functional groups on each monomer.
92
What are amino acids?
Amino acids are naturally occurring molecules essential for life. There are 20 naturally occurring amino acids.
93
What is the difference between condensation polymers and amino acid polymers?
An amino acid contains two different functional groups in a molecule like condensation polymers.
But the functional groups are different, they're a basic AMINO GROUP (NH2) and an acid CARBOXYL GROUP (COOH).
94
What is glycine?
Glycine is an amino acid.
It is the smallest and simplest amino acid possible.
95
How do amino acids form polymers?
Amino acids react by condensation polymerisation.
96
Describe how amino acids form polymers?
The AMINO GROUP of an acid can REACT with the ACID GROUP of another, and so on, to form a polymer chain. For every new bond that is formed a molecule of WATER is lost.
97
What are the polymers of amino acids known as?
Amino acids can form polymers known as POLYPEPTIDES.
98
Why are the polymers of amino acids known as polypeptides?
For example:
Glycine is the simplest amino acid and can be polymerised to form polyglycine.
An amide link is formed when one glycine molecule reacts with another; however, in Bio, amide links are called peptide bonds.
When many amino acids are joined, the polymer is called a polypeptide, in this case polyglycine.
99
What do polymers of amino acids form?
One or more LONG-CHAINS of polypeptides are known as PROTEINS.
100
What is the use of proteins in the body?
Proteins are used for the growth and repair of living cells.
For example:
- enzymes work as CATALYSTS
- haemoglobin TRANSPORTS OXYGEN
- ANTIBODIES form part of the IMMUNE SYSTEM
- the majority of BODY TISSUE is made from proteins
101
How can different proteins be formed?
Different proteins can be made from joining different COMBINATIONS (orders) of amino acids into the same polypeptide chain, allowing a huge variety of different proteins and enzymes to be made from just 20 amino acids.
102
What is DNA?
DNA (deoxyribonucleic acid) is a large molecule essential for life.
103
Where is DNA found?
DNA is found in EVERY living thing and many viruses.
104
What is the role of DNA?*
*DNA encodes genetic instructions for the development and functioning of living organisms and viruses.
105
Explain the role of DNA.
It contains GENETIC INSTRUCTIONS that allow the organism to develop and operate.
Simply, DNA is responsible for deciding which amino acids are joined together, and in what order, to form proteins and enzymes that decide what happens in a living organism.
106
What is the structure of DNA?
It's a large molecule that takes a DOUBLE HELIX structure.
107
Is DNA a polymer?
DNA is a polymer.
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How many types of monomer is DNA made up of?
Instead of 20 different monomers we saw with amino acids, DNA is made up of only 4.
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How many polymer chains is DNA formed from?
DNA is made up of TWO polymer chains of monomers called 'NUCLEOTIDES'.
The nucleotides each contain a small molecule known as a 'BASE'. There are four different bases, known by their initials- A, C, G, and T.
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How is DNA formed?
The bases on the different polymer chains pair up with each other and form CROSS LINKS keeping the two strands of nucleotides TOGETHER and giving the double helix structure.
The order of the bases acts as a CODE for an ORGANISM'S GENES.
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Name 4 naturally occurring polymers that are important for life.
Naturally occurring polymers important for life include proteins, starch and cellulose made from glucose monomer units, and DNA.
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What is sugar?
SUGARS are small molecules that contain CARBON, OXYGEN and HYDROGEN.
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How are polymers of sugar formed?
Sugars can react trough polymerisation reactions to form POLYMERS e.g. STARCH and CELLULOSE.
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How is starch and cellulose made?
Both are made from glucose monomer units.
When the links/bonds form in a line, starch is made; but when they form diagonally, cellulose is made.
The way they have joined-makes them different things.
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What is the function of a starch polymer?
Starch is used by cells as a FOOD STORE- potatoes and wheat grains contain starch which their respective plants have stored for future use.
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What is the function of cellulose as a polymer?
Cellulose makes up the CELL WALLS of plant cells, and gives green plants their rigid structure and ability to grow upwards towards light.
