Hydrocarbons
… The family (or homologous series) of hydrocarbons which has only single bonds between the carbon atoms is called the …?… family. The general formula for this family is…?
… The family of hydrocarbons which has a DOUBLE bond between a pair of carbon atoms is called the …?… family. The general formula of this homologous series is…?
Crude Oil and fuels
… Crude oil is a …?… of many different compounds that boil at different …?….
… Most of the compounds in crude oil are a…?… h…?…, which means they contain only hydrogen and carbon with single bonds.
Fractional Distillation
… A Fractionating Column separates crude oil into useful alkane f…?….
… Crude oil is pumped into the bottom of the column and …?… so that most of it …?… into gases.
… As you go up the fractionating column, the temperature …?…. Each fraction cools to its …?… point at a particular level in the column and …?… into a liquid which can be collected.
… Name three fractions of crude oil that could be collected from a fractionating column.
… Short chain hydrocarbons are more useful as fuels (compared to longer chains) because they are more f…?… (burn easily), less …?… (less sticky) and burn with a …?… flame (complete combustion).
… Alkanes are hydrocarbons with only single bonds. These are called …?… hydrocarbons.
… A feedstock is a raw material used to provide reactants for an industrial reaction. For example, ethene is produced from crude oil (via fractional distillation and then cracking) and is used as ‘feedstock’ to make poly(ethene), a polymer.
Combustion
… An o…?… reaction is when oxygen reacts with a substance (adding oxygen)
… A r…?… reaction is when oxygen is removed from a substance (think of “RidOxygen”!)
… Combustion of alkanes can be ‘complete’ forming the products …?… and …?…
… The chemical equation for the complete combustion of methane is:
CH4 + O2 —–> …?…. + …?….
Can you balance this equation?
… Incomplete combustion is if there is insufficient …?… . The products are …?…, carbon monoxide, water and particulates (e.g. carbon particles ‘soot’, unburnt hydrocarbons).
… Uncombusted particles of hydrocarbons and carbon form during incomplete combustion. These ‘particulates’ are a health hazard and can cause breathing problems, e.g. in high traffic areas.
… ‘Coke’ is a solid fuel made by heating coal in the absence of air so that the volatile components in the coal are driven off. It is therefore mostly made of carbon.
Reactions of the Alkenes
… Alkenes can react with oxygen in the same way as alkanes. This is called a c…?… reaction.
… Simple molecules such as the halogens, hydrogen and water can react with alkenes via their double bond, which springs open. This is called an a…?… reaction.
Cleaner fuels
… Many scientists believe that c…?… d…?… produced from burning fuels causes global warming.
… What environmental problem is caused by sulphur dioxide and nitrogen oxides?
… Name the product of incomplete combustion that scientists believe causes global dimming.
… Harmful substances from waste gases can be removed before they are released into the a…?….
For example, sulfur dioxide is removed from the waste gases produced by power stations and exhaust systems of cars are fitted with c…?… c…?… that turn carbon monoxide and nitrogen oxides into carbon dioxide.
… Sulphur can also be removed from fuels BEFORE they are burned so that less sulphur dioxide is produced.
Alternative fuels
… Biofuels such as b…?… (from vegetable oils) and e…?… (from plant sugars) are a renewable source of energy that could be used instead of fossil fuels.
… What is one advantages and one disadvantage of using biodiesel?
… Hydrogen is a potential fuel for the future because it only produces water when burned. However it is difficult to store and requires large amounts of energy to produce via electrolysis of water.
Cracking hydrocarbons
… AlkEnes can be made by ‘c…?…’ a long chain alkane by heating it with a ceramic c…?… so that smaller molecules are ‘cracked’ off the end. These smaller molecules will be a mixture of a…?… and a..?… (with a double bond) plus hydrogen.
… One method of cracking is to pass vapours of a long chain hydrocarbon over a hot (400-700°C) ceramic catalyst (e.g. Aluminium oxide). The other method is…?
… Cracking hydrocarbons is useful because…?
… “Cracking” is a type of reaction called t…?… d…?… where the molecule is broken up into shorter chains.
… Why are fractions with lower boiling points more useful as fuels?
Products from oil
… Ethanol is used for…?
… Shorter chain, cleaner…?
Making ethanol:
… by using fermentation. The word and symbol equations are…?
… by hydration of ethene – the word and symbol equations are…? What are the conditions needed for this reaction?
… What are the advantages and disadvantages of these methods?
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Alcohols
… Write out the equation for the reaction of ethene and steam to make ethanol.
What type of reaction is this?
What reaction conditions are required?
… In fermentation, what converts the sugar into ethanol?
What temperature is required for this reaction?
… Ethanol can be dehydrated to make ethene.
What is the chemical equation for this reaction?
What catalyst is required?
… What are the advantages and disadvantages of producing ethanol using the hydration of ethene vs. fermentation?
… The homologous series (‘family’) of alcohols contain the functional group…?
… What is the displayed formula, structural formula and molecular formula for propanol?
… What are some uses of alcohols?
… Alcohols burn in air (c…?…) to form…?
… Alcohols also react with sodium to form…?
… Ethanol can be o…?… producing ethanoic acid, either by chemical oxidising agents, or by m…?… in air.
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Carboxylic Acids
… The main acid in vinegar is …?… acid.
… What is the functional group of a carboxylic acid? (try drawing the displayed formula for ethanoic acid to show this).
… Carboxylic acids are weak acids, which means…?
… How does the pH of a weak acid compare to the pH of a strong acid?
… Write a balanced equation to show that ethanoic acid is a weak acid.
… Solutions of carboxylic acid react with carbonates. What would you observe?
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Esters
… Esters are v…?… organic compounds used for…?
… What is the functional group of an ester? (it’s easiest to show this if you draw the display formula for ethyl ethanoate for example)
… Esters, such as ethyl ethanoate, are made by reacting a c…?… a…?… with an a…?… in the presence of an a…?… c…?…
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Organic chemistry Issues
… Organic chemicals have many uses in society including solvents, alcohol for beverages, biofuels, perfumes and flavourings.
… Some organic substances, however, such as ethanol and solvents can be abused.
… As crude oil supplies run out, alcohols made from growing crops could be used instead as biofuels.
… The future use of biofuels might conflict with the need to feed the world.
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Making polymers from alkenes (addition polymerisation)
… Alkene monomers are useful to make plastics
… Monomers always have a …?… bond which springs open to join with other monomers in a reaction called a…?… p…?… . This forms a very long chain molecule called a p…?… (a plastic).
… You can have different types of monomers, for example with chlorine as one of the atoms bonded to a carbon. These form polymers with different physical and chemical properties.
… The same polymer, but with different physical properties (strength, density) can be made by reacting the monomers under different r…?… c…?….
… An example of a smart polymer is…?
… What are the environmental problems caused by different polymers?
… What are some ways to reduce the problems of plastic rubbish?
… What does biodegradable mean?
… Cornstarch can be mixed in with a non-biodegradable polymer. M….?…. in soil break down the cornstarch so the plastic breaks down into very small pieces that can be mixed with soil or compost.
… Fully biodegradable plastics can also be made from plant material such as cornstarch, for example in food packaging.
… Thermosetting polymers have strong ‘c…?… – l…?…’ bonds between hydrocarbon chains. This means that the polymer does not soften when …?… – it remains rigid.
… Thermosoftening polymers have no ‘c…?… – l…?…’ bonds between hydrocarbon chains. The inter-molecular forces are weak and easily broken by heat, so the polymer can be softened.
… Condensation polymerisation does not require double bonds.
When these types of monomers react, they join together, usually losing small molecules such as water, hence the name ‘condensation reaction’.
The simplest polymers are produced from two different monomers with two of the same functional groups on each monomer. For example:
HOOC-CH2-CH2-COOH + HO-CH2-CH2-CH2-CH2-OH
or simplified:
HOOC-□-COOH + HO-△-OH → HOOC-□-COO-△-OH + H2O
Where the □ and △ symbols represent a carbon hydrocarbon chain such as – CH2 – CH2 –
And now the polymerisation reaction:
n(HOOC-□-COOH) + n(HO-△-OH) → [-□-COO-△-COO-]n + 2n(H2O)
In this reaction we have formed multiple ester functional groups in the polymer. The product would be called a type of ‘polyester’.
Condensation polymers can also be made using monomers which have two different functional groups on each monomer. For example:
HOOC-□-NHH + HOOC-△-NHH → HOOC-□-NHCO-△-NHH + H2O
In this reaction we have formed multiple amide functional groups in the polymer. The product would be called a type of ‘polyamide’.
An AMINO ACID has two different functional groups in its molecule. Amino acids react by condensation polymerisation to produce POLYPEPTIDES.
For example: glycine polymerises to produce the polypeptide:
n(HOOC-CH2-NHH) → (-CO-CH2-NH-)n + n H2O
Different amino acids polymerise to form PROTEINS.
DNA (deoxyribonucleic acid) is a large molecule essential for life. DNA encodes genetic instructions for the development and functioning of living organisms and viruses.
Most DNA molecules are two polymer chains, made from four different monomers called NUCLEOTIDES, in the form of a double helix. Other naturally occurring polymers important for life include proteins, starch and cellulose.
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Plant oils
… Two types of biofuels include bio-…?… and bio-ethanol made from vegetable crops.
… The methods used to extract plant oils include c…?…, p…?… and d…?…
… Why are vegetable oils important foods?
… Why are vegetable oils useful for cooking?
… Apart from colour, state two ways in which a food cooked in olive oil will be different to a food cooked in water.
… What is meant by hardening vegetable oils? What reaction conditions are needed?
… What is the test for unsaturated oils?
… How do emulsifiers work?
… What does an emulsifier do in cooking? The resulting mixture is called an …?…
… An emulsion makes the t…?… of the food more palatable.
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