AQA Jan 2013 Paper 2 Q5

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do not write outside the box glucose is an organic molecule glucose can exist in different forms in aqueous solution a in aqueous solution some glucose molecules have the following structure h oh oh oh c o h oh oh a i deduce the empirical formula of glucose mark a ii consider the infrared spectrum of solid glucose transmittance wavenumber cm state why it is possible to suggest that in the solid state very few molecules have the structure shown you may find it helpful to refer to table on the data sheet mark wmp jan chem do not write outside the box b in the absence of oxygen an aqueous solution of glucose can be fermented to produce ethanol for use in alcoholic drinks write an equation for this fermentation reaction give two other essential conditions for the production of ethanol in this fermentation equation condition condition marks c any ethanol present in the breath of a drinker can be detected by using a breathalyser the ethanol is converted into ethanoic acid the breathalyser has negative and positive electrodes a current is measured and displayed in terms of alcohol content the overall redox equation is as follows ch ch oh i o g ch cooh i h o i c i draw the displayed formula for ethanoic acid c ii deduce a half equation for the reduction of atmospheric oxygen to water in acidic solution at one electrode of the breathalyser mark mark c iii deduce a half equation for the oxidation of ethanol in water to ethanoic acid at the other electrode of the breathalyser mark question continues on the next page turn over wmp jan chem do not write outside the box c iv the earliest breathalysers used laboratory chemicals to oxidise the ethanol to ethanoic acid detection was by a colour change identify a reagent or combination of reagents that you would use in the laboratory to oxidise ethanol to ethanoic acid state the colour change that you would expect to see reagent or combination of reagents colour change marks d the fermentation of glucose from crops is the main method for the production of ethanol the product is called bioethanol the european union has declared that bioethanol is carbon neutral d i state the meaning of the term carbon neutral mark extra space d ii other than carbon neutrality state the main advantage of the use of glucose from crops as the raw material for the production of ethanol mark d iii give one disadvantage of the use of crops for the production of ethanol mark wmp jan chem

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