AQA AS Specimen Paper 2 Q4

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10 Glucose can decompose in the presence of microorganisms to form a range of products. One of these is a carboxylic acid (Mr = 88.0) containing 40.9% carbon and 4.5% hydrogen by mass. . 1 0 4 [4 marks] Deduce the empirical and molecular formulas of the carboxylic acid formed. Empirical formula = Molecular formula = . 2 0 4 Ethanol is formed by the fermentation of glucose. A student carried out this fermentation reaction in a beaker using an aqueous solution of glucose at a temperature of 25 C in the presence of yeast. Write an equation for the reaction occurring during fermentation. . 3 0 4 In industry, this fermentation reaction is carried out at 35 C rather than 25 C. Suggest one advantage and one disadvantage for industry of carrying out the fermentation at this higher temperature. [1 mark] [2 marks] Advantage Disadvantage Barcode Typesetter code<br /> . 4 0 4 . 5 0 4 11 The method used by the student in Question 4.2 would result in the ethanol being contaminated by ethanoic acid. How does this contamination occur? [1 mark] Give two differences between the infrared spectrum of a carboxylic acid and that of an alcohol other than in their fingerprint regions. Use Table A on the Data Sheet. [2 marks] Difference 1 Difference 2 Turn over for the next question Barcode Typesetter code Turn over <br />

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