4 Organic chemistry
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(a) Introduction
Know that a hydrocarbon is a compound of hydrogen and carbon only
Understand how to represent organic molecules using empirical formulae, molecular formulae, general formulae, structural formulae and displayed formulae
Know what is meant by the terms homologous series, functional group and isomerism
Understand how to name compounds relevant to this specification using the rules of International Union of Pure and Applied Chemistry (IUPAC) nomenclature students will be expected to name compounds containing up to six carbon atoms
Understand how to write the possible structural and displayed formulae of an organic molecule given its molecular formula
Understand how to classify reactions of organic compounds as substitution, addition and combustion knowledge of reaction mechanisms is not required
(b) Crude oil
Know that crude oil is a mixture of hydrocarbons
Describe how the industrial process of fractional distillation separates crude oil into fractions
Know the names and uses of the main fractions obtained from crude oil: refinery gases, gasoline, kerosene, diesel, fuel oil and bitumen
Know the trend in colour, boiling point and viscosity of the main fractions
Know that a fuel is a substance that, when burned, releases heat energy
Know the possible products of complete and incomplete combustion of hydrocarbons with oxygen in the air
Understand why carbon monoxide is poisonous, in terms of its effect on the capacity of blood to transport oxygen references to haemoglobin are not required
Know that, in car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming oxides of nitrogen
Explain how the combustion of some impurities in hydrocarbon fuels results in the formation of sulfur dioxide
Understand how sulfur dioxide and oxides of nitrogen contribute to acid rain
Describe how long-chain alkanes are converted to alkenes and shorter-chain alkanes by catalytic cracking (using silica or alumina as the catalyst and a temperature in the range of 600-700 ºC)
Explain why cracking is necessary, in terms of the balance between supply and demand for different fractions
(c) Alkanes
Know the general formula for alkanes
Explain why alkanes are classified as saturated hydrocarbons
Understand how to draw the structural and displayed formulae for alkanes with up to five carbon atoms in the molecule, and to name the unbranched-chain isomers
Describe the reactions of alkanes with halogens in the presence of ultraviolet radiation, limited to mono-substitution knowledge of reaction mechanisms is not required
(d) Alkenes
Know that alkenes contain the functional group >C=C<
Know the general formula for alkenes
Explain why alkenes are classified as unsaturated hydrocarbons
Understand how to draw the structural and displayed formulae for alkenes with up to four carbon atoms in the molecule, and name the unbranched-chain isomers knowledge of cis/trans or E/Z notation is not required
Describe the reactions of alkenes with bromine to produce dibromoalkanes
Describe how bromine water can be used to distinguish between an alkane and an alkene
(e) Alcohols
Know that alcohols contain the functional group -OH
Understand how to draw structural and displayed formulae for methanol, ethanol, propanol (propan-1-ol only) and butanol (butan-1-ol only), and name each compound the names propanol and butanol are acceptable
Know that ethanol can be oxidised by: • burning in air or oxygen (complete combustion) • reaction with oxygen in the air to form ethanoic acid (microbial oxidation) • heating with potassium dichromate(VI) in dilute sulfuric acid to form ethanoic acid
Know that ethanol can be manufactured by: • reacting ethene with steam in the presence of a phosphoric acid catalyst at a temperature of about 300 ºC and a pressure of about 60-70 atm • the fermentation of glucose, in the absence of air, at an optimum temperature of about 30 ºC and using the enzymes in yeast
Understand the reasons for fermentation, in the absence of air, and at an optimum temperature
(f) Carboxylic acids
4.34CCarboxylic acid functional group
Know that carboxylic acids contain the –COOH functional group.
4.35CCarboxylic acid structures and names
Understand how to draw structural and displayed formulae for unbranched-chain carboxylic acids with up to four carbon atoms in the molecule, and name each compound
4.36CCarboxylic acid reactions
Describe the reactions of aqueous solutions of carboxylic acids with metals and metal carbonates
4.37CVinegar and ethanoic acid
Know that vinegar is an aqueous solution containing ethanoic acid
(g) Esters
Know that esters contain the –COO– functional group.
Know that ethyl ethanoate is the ester produced when ethanol and ethanoic acid react in the presence of an acid catalyst
Understand how to write the structural and displayed formulae of ethyl ethanoate
Understand how to write the structural and displayed formulae of an ester, given the name or formula of the alcohol and carboxylic acid from which it is formed and vice versa
Know that esters are volatile compounds with distinctive smells and are used as food flavourings and in perfumes
Practical: prepare a sample of an ester such as ethyl ethanoate
(h) Synthetic polymers
Know that an addition polymer is formed by joining up many small molecules called monomers
Understand how to draw the repeat unit of an addition polymer, including poly(ethene), poly(propene), poly(chloroethene) and (poly)tetrafluoroethene
Understand how to deduce the structure of a monomer from the repeat unit of an addition polymer and vice versa
Explain problems in the disposal of addition polymers, including: • their inertness and inability to biodegrade • the production of toxic gases when they are burned.
Know that condensation polymerisation, in which a dicarboxylic acid reacts with a diol, produces a polyester and water
Write the structural and displayed formula of a polyester repeat unit from its monomers, including ethanedioic acid reacting with ethanediol.
Know that some polyesters, known as biopolyesters, are biodegradable