2 Condensation Polymers

 

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3.12 Polymers Page 1 - 2

Oxford Textbook Pages : 450 - 454

CGP Revision Guide Pages : 178 - 179

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Show Specification Ref : 3.3.12.1

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Question 1 / 5

AQA Jun 2010 Paper 4 Q7 section b answer all questions in the spaces provided do not write outside the box esters have many important commercial uses such as solvents and artificial flavourings in foods esters can be prepared in several ways including the reactions of alcohols with carboxylic acids acid anhydrides acyl chlorides and other esters a ethyl butanoate is used as a pineapple flavouring in sweets and cakes write an equation for the preparation of ethyl butanoate from an acid and an alcohol give a catalyst used for the reaction marks wmp jun chem b butyl ethanoate is used as a solvent in the pharmaceutical industry do not write outside the box write an equation for the preparation of butyl ethanoate from an acid anhydride and an alcohol marks c name and outline a mechanism for the reaction of ch cocl with ch oh to form an ester question continues on the next page marks turn over wmp jun chem do not write outside the box d the ester shown below occurs in vegetable oils write an equation to show the formation of biodiesel from this ester ch oocc h choocc h ch oocc h marks wmp jun chem do not write outside the box e draw the repeating unit of the polyester terylene that is made from benzene dicarboxylic acid and ethane diol although terylene is biodegradeable it is preferable to recycle objects made from terylene give one advantage and one disadvantage of recycling objects made from terylene marks turn over for the next question turn over wmp jun chem
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Question 2 / 5

AQA Jun 2011 Paper 4 Q4 do not write outside the box the amide or peptide link is found in synthetic polyamides and also in naturally occurring proteins a i draw the repeating unit of the polyamide formed by the reaction of propanedioic acid with hexane diamine a ii in terms of the intermolecular forces between the polymer chains explain why polyamides can be made into fibres suitable for use in sewing and weaving whereas polyalkenes usually produce fibres that are too weak for this purpose marks marks extra space wmp jun chem do not write outside the box b i name and outline a mechanism for the reaction of ch ch cocl with ch nh name of mechanism mechanism b ii give the name of the product containing an amide linkage that is formed in the reaction in part b i mark c the dipeptide shown below is formed from two different amino acids marks ch cooh h n c c n c ch sh h o h h draw the structure of the alternative dipeptide that could be formed by these two amino acids question continues on the next page mark turn over wmp jun chem d the amino acids serine and aspartic acid are shown below do not write outside the box ch oh cooh h c cooh h c ch cooh nh serine nh aspartic acid d i give the iupac name of serine mark d ii draw the structure of the species formed when aspartic acid reacts with aqueous sodium hydroxide d iii draw the structure of the species formed when serine reacts with dilute hydrochloric acid mark mark d iv draw the structure of the species formed when serine reacts with an excess of bromomethane mark wmp jun chem
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Question 3 / 5

AQA Jun 2011 Paper 4 Q5 do not write outside the box items softened with plasticisers have become an essential part of our modern society compound s shown below is commonly known as phthalic acid esters of phthalic acid are called phthalates and are used as plasticisers to soften polymers such as pvc poly chloroethene cooh cooh a give the iupac name for phthalic acid mark b draw the displayed formula of the repeating unit of poly chloroethene mark question continues on the next page turn over wmp jun chem do not write outside the box c the ester diethyl phthalate dep is used in food packaging and in cosmetics c i complete the following equation showing the formation of dep from phthalic anhydride cooch ch cooch ch dep marks c ii deduce the number of peaks in the c n m r spectrum of dep mark c iii one of the peaks in the c n m r spectrum of dep is at ppm table on the data sheet can be used to identify a type of carbon atom responsible for this peak draw a circle around one carbon atom of this type in the structure below cooch ch cooch ch d the mass spectrum of dep includes major peaks at m z the molecular ion and at m z write an equation to show the fragmentation of the molecular ion to form the fragment that causes the peak at m z mark marks wmp jun chem do not write outside the box e because of their many uses phthalates have been tested for possible adverse effects to humans and to the environment the european council for plasticisers and intermediates is an organisation that represents the manufacturers of plasticisers the text below is taken from a document written by the organisation research demonstrates that phthalates at current and foreseeable exposure levels do not pose a risk to human health or to the environment experimental evidence shows that phthalates are readily biodegradable and do not persist for long in the environment e i hydrolysis of dep in an excess of water was found to follow first order kinetics write a rate equation for this hydrolysis reaction using dep to represent the ester mark e ii suggest what needs to be done so that the public could feel confident that the research quoted above is reliable marks extra space turn over wmp jun chem
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Question 4 / 5

AQA Jun 2012 Paper 4 Q4 do not write outside the box a acyl chlorides and acid anhydrides are important compounds in organic synthesis outline a mechanism for the reaction of ch ch cocl with ch oh and name the organic product formed mechanism name of organic product marks b a polyester was produced by reacting a diol with a diacyl chloride the repeating unit of the polymer is shown below o c ch ch c o ch ch ch ch ch b i name the diol used mark b ii draw the displayed formula of the diacyl chloride used mark wmp jun chem do not write outside the box b iii a shirt was made from this polyester a student wearing the shirt accidentally splashed aqueous sodium hydroxide on a sleeve holes later appeared in the sleeve where the sodium hydroxide had been name the type of reaction that occurred between the polyester and the aqueous sodium hydroxide explain why the aqueous sodium hydroxide reacted with the polyester type of reaction explanation marks c i complete the following equation for the preparation of aspirin using ethanoic anhydride by writing the structural formula of the missing product cooh oh h c h c cooh aspirin ch mark c ii suggest a name for the mechanism for the reaction in part c i mark c iii give two industrial advantages other than cost of using ethanoic anhydride rather than ethanoyl chloride in the production of aspirin advantage advantage marks question continues on the next page turn over wmp jun chem do not write outside the box d complete the following equation for the reaction of one molecule of benzene dicarboxylic anhydride phthalic anhydride with one molecule of methanol by drawing the structural formula of the single product ch oh e the indicator phenolphthalein is synthesised by reacting phthalic anhydride with phenol as shown in the following equation mark oh conc h so heat oh c oh h o phenol phenolphthalein e i name the functional group ringed in the structure of phenolphthalein mark e ii deduce the number of peaks in the c n m r spectrum of phenolphthalein mark e iii one of the carbon atoms in the structure of phenolphthalein shown above is labelled with an asterisk use table on the data sheet to suggest a range of values for the peak due to this carbon atom in the c n m r spectrum of phenolphthalein mark wmp jun chem do not write outside the box f phenolphthalein can be used as an indicator in some acid alkali titrations the ph range for phenolphthalein is f i for each acid alkali combination in the table below put a tick in the box if phenolphthalein could be used as an indicator acid alkali tick box sulfuric acid sodium hydroxide hydrochloric acid ammonia ethanoic acid potassium hydroxide nitric acid methylamine f ii in a titration nitric acid is added from a burette to a solution of sodium hydroxide containing a few drops of phenolphthalein indicator give the colour change at the end point mark marks turn over for the next question turn over wmp jun chem
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Question 5 / 5

AQA Jun 2013 Paper 4 Q5 do not write outside the box lactic acid ch ch oh cooh is formed in the human body during metabolism and exercise this acid is also formed by the fermentation of carbohydrates such as sucrose c h o a i give the iupac name for lactic acid mark a ii write an equation for the formation of lactic acid from sucrose and water mark b a molecule of lactic acid contains an asymmetric carbon atom the lactic acid in the body occurs as a single enantiomer a racemic mixture racemate of lactic acid can be formed in the following two stage synthesis ch c o stage hcn ch c cn oh stage ch c cooh oh b i name and outline a mechanism for stage name of mechanism mechanism marks wmp jun chem do not write outside the box b ii give the meaning of the term racemic mixture racemate mark b iii explain how you could distinguish between a racemic mixture racemate of lactic acid and one of the enantiomers of lactic acid marks c a mixture of lactic acid and its salt sodium lactate is used as an acidity regulator in some foods an acidity regulator makes sure that there is little variation in the ph of food c i write an equation for the reaction of lactic acid with sodium hydroxide mark c ii the acid dissociation constant ka for lactic acid has the value mol dm at k calculate the ph of an equimolar solution of lactic acid and sodium lactate marks question continues on the next page turn over wmp jun chem do not write outside the box c iii suggest an alternative name for the term acidity regulator explain how a mixture of lactic acid and sodium lactate can act as a regulator when natural processes increase the acidity in some foods name explanation marks extra space d the cup shown is made from pla poly lactic acid pla is the condensation polymer formed from lactic acid the polymer is described as biodegradable and compostable compostable material breaks down slowly in contact with the moist air in a garden bin this produces compost that can be used to improve soil the manufacturers stress that pla cups differ from traditional plastic cups that are neither biodegradable nor compostable d i draw a section of pla that shows two repeating units marks wmp jun chem do not write outside the box d ii name the type of condensation polymer in pla mark d iii an intermediate in the production of pla is a cyclic compound c h o that is formed from two pla molecules draw the structure of this cyclic compound d iv traditional non biodegradable plastic cups can be made from poly phenylethene commonly known as polystyrene draw the repeating unit of poly phenylethene mark mark d v the manufacturers of pla claim that the material will break down to compost in just weeks suggest one reason why pla in landfill may take longer than weeks to break down mark turn over wmp jun chem
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