1) We learned two main things in 9.2.2.
a) That biomass (cellulose) has the potential to be converted into glucose, then ethanol (which can be used as an alternative fuel) then ethene (which can be used as a raw material for chemicals). Many people ignored the fact that this cellulose derived ethene was a source of future chemicals
b) That biopolymers (derived from bacteria or biomass nutrients) – eg PHB have been developed over time (ie A. Eutrophus to GM E.coli to GM plants), are biodegradeable, have some limited applications but there are still many obstacles for them to replace petrochemical polymers
2) Biopolymers are not replacement fuels. They are replacement plastics. Technically burning wood (cellulose) is burning a biopolymer for energy but that is not the point of our studies in the Chemistry course.
3) Many students did not ANSWER THE QUESTION. If the question mentions a biopolymer you must talk about PHB, if it mentions biomass you must talk about cellulose, if it mentions current developments you must talk about PHB’s move from A. Eutrophus to GM E.coli to GM plants. If it mentions USES you must talk about specific applications. If it gives you a stimulus (eg a Blog quote) you MUST refer to it in your answer.
4) Make sure you include the CHEMISTRY. You need to demonstrate you are a better Chemistry students than the next person. If you only give a general answer (that any non-Chemistry trained person could write) you will only get (approx) half the available marks. That means write chemical equations, use chemical terms, whrever you can include descriptions of specific chemical compounds and processes.
2002
Q18) Assess means +, - and judgement. This Q is about developments in a biopolymer thus you need to name the biopolymer (PHB) say how it was originally produced and how advances have increased production rates (ie A. Eutrophus to GM E.coli to GM plants). You should say its applications (and advantages eg biodegradable) and disadvantages ie limited uses and production and a judgement – ie developments have allowed more to be produced but applications are still limited (especially compared to petrochemical polymers)
2003
Q20) You must note that cellulose if the main component of biomass. You must say how cellulose can be converted into ethanol and how this is a replacement fuel (ie eqn for combustion). You must say how ethanol can be converted to ethene and thus can replace chemicals (eqn good). You must say the advantages – ie renewable, less polluting and disadvantages (eg land use, expense, energy concerns) and then make a judgement (especially in light of crude oil ‘running out’)
2005
Q18) Again the Q says development so a little on developments (ie making more and using more because we have gone from A. Eutrophus to GM E.coli to GM plants) You then need to say the advantages on the environment compared to traditional (ie renewable and biodegradable) and then the applications and impact on society – but don’t oversell – being used for razor handles etc has not ‘changed the world’ – you could use this as a negative and note its limitations (properties and production) have meant only limited applications. Then give a judgement (ie has potential…)
2006
Q6) we did this Q in class – don’t forget that for condensation polymerisation if you have (n) monomers you lose (n-1) water molecules …
2010
Q30a) You must show the full equation (reactants and products – with correct formulae) and must label them as condensation or addition
Q30b) We have done this a number of times : to answer this question you need to describe the structure and link this to properties and link this to uses. Also when you name the polymer you must specify which monomer it comes from. VERY IMPORTANT – the bonds between chains are NOT covalent. They are intermolecular bonds and are usually weak dispersion bonds (but because the chains are so long these bonds are quite strong overall), but can be H-bonds when there are OH groups in the chains (eg cellulose).
2011
Q27) Be careful to read the Q – you had to include USES (2nd word of question) of a NAMED biopolymer (ie you had to say PHB) you had to mention the properties of both polymers (eg biodegradable vs non-biodegradable) and refer to the blog. Better answers noted polystyrenes properties and uses and noted that they were short term uses but because they were non-biodegradable they had specific impacts on living systems (ie relate to blog quote). They then contrasted this to PHB’s properties and applications and biodegradability noting the possibility of less environmental impact.
2002
Q18) Assess means +, - and judgement. This Q is about developments in a biopolymer thus you need to name the biopolymer (PHB) say how it was originally produced and how advances have increased production rates (ie A. Eutrophus to GM E.coli to GM plants). You should say its applications (and advantages eg biodegradable) and disadvantages ie limited uses and production and a judgement – ie developments have allowed more to be produced but applications are still limited (especially compared to petrochemical polymers)
2003
Q20) You must note that cellulose if the main component of biomass. You must say how cellulose can be converted into ethanol and how this is a replacement fuel (ie eqn for combustion). You must say how ethanol can be converted to ethene and thus can replace chemicals (eqn good). You must say the advantages – ie renewable, less polluting and disadvantages (eg land use, expense, energy concerns) and then make a judgement (especially in light of crude oil ‘running out’)
2005
Q18) Again the Q says development so a little on developments (ie making more and using more because we have gone from A. Eutrophus to GM E.coli to GM plants) You then need to say the advantages on the environment compared to traditional (ie renewable and biodegradable) and then the applications and impact on society – but don’t oversell – being used for razor handles etc has not ‘changed the world’ – you could use this as a negative and note its limitations (properties and production) have meant only limited applications. Then give a judgement (ie has potential…)
2006
Q6) we did this Q in class – don’t forget that for condensation polymerisation if you have (n) monomers you lose (n-1) water molecules …
2010
Q30a) You must show the full equation (reactants and products – with correct formulae) and must label them as condensation or addition
Q30b) We have done this a number of times : to answer this question you need to describe the structure and link this to properties and link this to uses. Also when you name the polymer you must specify which monomer it comes from. VERY IMPORTANT – the bonds between chains are NOT covalent. They are intermolecular bonds and are usually weak dispersion bonds (but because the chains are so long these bonds are quite strong overall), but can be H-bonds when there are OH groups in the chains (eg cellulose).
You need to choose three different polymers but at least
one needs to be from ethene and one from glucose.So, what polymer comes directly from glucose? Then I would choose two of the polymers that start with
ethene - you could possibly get away with ldpe and hdpe but BOS might count
them as the 'same' polymer...
2011
Q27) Be careful to read the Q – you had to include USES (2nd word of question) of a NAMED biopolymer (ie you had to say PHB) you had to mention the properties of both polymers (eg biodegradable vs non-biodegradable) and refer to the blog. Better answers noted polystyrenes properties and uses and noted that they were short term uses but because they were non-biodegradable they had specific impacts on living systems (ie relate to blog quote). They then contrasted this to PHB’s properties and applications and biodegradability noting the possibility of less environmental impact.
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