3 Introduction to mechanisms

 

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4.1.1 basic concepts and hydrocarbons Page 6

Oxford Textbook Pages : 184 - 186

CGP Revision Guide Pages : 90

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Show Specification Ref : 4.1.1f, 4.1.1g, 4.1.1h, 4.1.1i

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Question 1 / 5

AQA Jun 2012 Paper 2 Q6 do not write outside the box chloromethanes such as dichloromethane and trichloromethane are produced in industry as they have many uses trichloromethane has been used in the manufacture of the refrigerant chlorodifluoromethane a chlorine can react with dichloromethane ch cl to form trichloromethane chcl a i write an equation for each of the following steps in the mechanism for this reaction initiation step first propagation step second propagation step marks a ii give one essential condition for this reaction and name the type of mechanism essential condition type of mechanism marks question continues on the next page turn over wmp jun chem do not write outside the box b an organic product x with mr is obtained when chlorine reacts with trichloromethane b i write an equation for the overall reaction of chlorine with trichloromethane to form x by the same mechanism as that outlined in part a i mark b ii the following infrared spectrum was obtained for a sample of x produced in this reaction transmittance wavenumber cm use this infrared spectrum to explain why it is possible to deduce that this sample of x contains no trichloromethane you may find it helpful to refer to table on the data sheet marks extra space wmp jun chem do not write outside the box c explain with the aid of equations and the intermediates that form in the ozone layer why the european union has banned the use of chlorodifluoromethane chclf as a refrigerant marks extra space d the compound tetrafluoropropene is the refrigerant used in all new car air conditioners d i draw the displayed formula for tetrafluoropropene d ii give one reason why tetrafluoropropene is a more environmentally acceptable refrigerant than chlorodifluoromethane mark mark turn over wmp jun chem
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Question 2 / 5

AQA Jun 2012 Paper 2 Q7 do not write outside the box alkenes are useful intermediates in the synthesis of organic compounds a i complete the elimination mechanism by drawing appropriate curly arrows ho h h h ch c c c ch ch ch ch ch chch ch h o br h h br bromohexane hex ene a ii draw structures for the e and z stereoisomers of hex ene e isomer of hex ene z isomer of hex ene marks marks a iii state the meaning of the term stereoisomers marks extra space wmp jun chem do not write outside the box b the equation for the first reaction in the conversion of hex ene into hexan ol is shown below ch ch ch chch ch h so ch ch ch ch oso oh ch ch outline a mechanism for this reaction marks turn over for the next question turn over wmp jun chem
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Question 3 / 5

AQA Jun 2012 Paper 2 Q8 section b answer all questions in the spaces provided do not write outside the box the reaction of butane diol with butanedioic acid produces the polymer pbs used in biodegradable packaging and disposable cutlery butanedioic acid is produced by two different processes process l aqueous sodium hydroxide reacts with dibromobutane to make butane diol l butane diol is oxidised to butanedioic acid process l glucose reacts with carbon dioxide in the presence of microorganisms to produce butanedioic acid directly l the carbon dioxide used in this process is obtained from a local factory that produces bioethanol a deduce one safety reason and one environmental reason why process is preferred to process marks extra space wmp jun chem do not write outside the box b i name and outline a mechanism for the following reaction that occurs in process brch ch ch ch br naoh brch ch ch ch oh nabr marks question continues on the next page turn over wmp jun chem do not write outside the box b ii the infrared spectra shown are those of three compounds compound a dibromobutane compound b butane diol compound c butanedioic acid identify the compound responsible for each spectrum by writing the correct letter a b or c in the box next to each spectrum you may find it helpful to refer to table on the data sheet transmittance wavenumber cm transmittance wavenumber cm transmittance wavenumber cm marks wmp jun chem do not write outside the box c in the production of bioethanol glucose c h o is converted into a dilute aqueous solution of ethanol and carbon dioxide give the name of this process and state three essential conditions necessary to produce a good yield of ethanol marks extra space d state the class of alcohols to which the diol butane diol belongs identify a suitable reagent or combination of reagents for the conversion of butane diol into butanedioic acid hoocch ch cooh write an equation for this oxidation reaction using o to represent the oxidising agent marks extra space turn over wmp jun chem
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Question 4 / 5

AQA Jun 2015 Paper 2 Q8 section b do not write outside the box answer all questions in the spaces provided consider the following scheme of reactions ch reaction ch h c c ch ch h c c chcl ch reaction ch ch ch reaction h c c ch nh ch ch a give the iupac name for compound p and that for compound q marks p q wmp jun chem do not write outside the box b the conversion of p into q in reaction uses hcl name and outline a mechanism for this reaction marks c the conversion of q into r in reaction uses nh name and outline a mechanism for this reaction marks question continues on the next page turn over wmp jun chem do not write outside the box d state the type of reaction shown by reaction identify a reagent for this reaction give one condition necessary for a high yield of product when q is converted into p marks e hydrogen bromide hbr could be used in the overall conversion of p into r instead of using hcl hydrogen bromide is made by the reaction of nabr with concentrated phosphoric acid concentrated sulfuric acid is not used to make hbr from nabr write an equation for the reaction of nabr with h po to produce hbr and na po only identify two toxic gases that are formed together with hbr when nabr reacts with concentrated h so state the role of h so in the formation of these two toxic gases marks wmp jun chem
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Question 5 / 5

AQA Jun 2014 Paper 4 Q5 do not write outside the box a the carbonyl compound ch ch cho reacts very slowly with hcn name and outline a mechanism for the reaction of ch ch cho with hcn marks name of mechanism mechanism b the reaction in question a produces a pair of enantiomers b i draw the structure of each enantiomer to show how they are related to each other marks wmp jun chem b ii state and explain how you could distinguish between the two enantiomers do not write outside the box marks c give the iupac name of the product of the reaction in question a mark d in practice kcn rather than hcn is added to the carbonyl compound given that ka for hcn mol dm suggest why the reaction with hcn is very slow marks question continues on the next page turn over wmp jun chem do not write outside the box e acrylic fibres are used as a substitute for wool acrylics are copolymers of acrylonitrile with other compounds acrylonitrile is the common name for the following compound e i acrylonitrile can be formed from propene h c ch c n write an equation for the reaction of propene with ammonia and oxygen to form acrylonitrile and one other product mark e ii the term copolymer is used to describe the product obtained when two or more different monomers form a polymer draw the repeating unit of the acrylic copolymer that contains acrylonitrile monomer and chloroethene monomer mark e iii name the type of polymerisation involved in question e ii mark wmp jun chem turn over for the next question do not write on this page answer in the spaces provided turn over wmp jun chem
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