Edexcel Jun 2017 Paper 2 Q19

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19 This is a question about alcohols and compounds made from them. (a) (i) Complete the table about some of the structural isomers with the molecular formula C5H12O. Name Skeletal Formula Classification 2,2-dimethylpropan-1-ol Primary Secondary OH OH OH 3-methylbutan-1-ol 2-methylbutan-2-ol (ii) Identify, by name or formula, the alcohol which is the branched structural isomer with molecular formula C5H12O that is not in the table. (3) (1) A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D *P53493A01120* 11 Turn over<br /> (iii) Explain why 2,2-dimethylpropan-1-ol has a significantly lower boiling temperature than the isomer pentan-1-ol. (2)D O N O T W R I T E I N T H I S A R E A (iv) Draw a hydrogen bond between a water molecule and the pentan-1-ol molecule. Clearly label the bond angle about the hydrogen involved in the hydrogen bond. (2) H C C C C C O 12 *P53493A01220* D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A<br /> (b) Ethanol, C2H5OH, can be oxidized to ethanoic acid, CH3COOH. (i) Give the formula of a suitable oxidizing agent and the conditions required. (2) Oxidizing agentConditions(ii) Using the symbol, [O], for the oxidizing agent, write the equation for the oxidation of ethanol to ethanoic acid. State symbols are not required. (iii) Draw, and fully label, the apparatus that would be used to carry out the complete oxidation of ethanol to ethanoic acid. Include any material that would be used to ensure that boiling is controlled and not violent. (1) (3) A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D *P53493A01320* 13 Turn over<br /> (c) A sample of ethanol was oxidized completely. After separation, 5.00 g of a mixture of ethanoic acid and water was obtained. The mixture was added to a 500 cm3 volumetric flask, made up to the mark with deionized water and shaken thoroughly. The concentration of this diluted solution was determined by titration with sodium hydroxide solution, of concentration 0.200 mol dm3. The following results were obtained using 25.0 cm3 pipetted aliquots of this diluted ethanoic acid solution. Titration Final volume /cm3 Initial volume /cm3 Volume added /cm3 Trial 14.20 0.00 14.20 19.50 5.00 14.50 34.45 20.00 14.45 49.00 34.45 14.55 Mean titre = 14.50 cm3 (i) State what is unusual about the value of the trial titre. Suggest a possible fault with the use of a pipette that could explain this value. You may assume that the bottom of the meniscus was correctly aligned to the mark on the pipette. (2)(ii) The reaction between ethanoic acid and sodium hydroxide has a 1:1 mole ratio. Calculate the concentration of the diluted ethanoic acid solution in mol dm3. (2) 14 *P53493A01420* D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A<br /> (iii) Calculate the mass of ethanoic acid in 500 cm3 of the diluted solution. (d) Alcohols can undergo complete or incomplete combustion. (i) Write the equation for the complete combustion of hexan-1-ol, C6H13OH. State symbols are not required. (ii) Write the equation for the incomplete combustion of hexan-1-ol which produces only carbon and water. State symbols are not required. (iii) Calculate the volume of oxygen, measured at room temperature and pressure, required for the complete combustion of one mole of hexan-1-ol. State the likely observation if 500 dm3 of air containing 20% of oxygen was present for the combustion of one mole of hexan-1-ol. Justify your answer. [Molar volume = 24.0 dm3 mol1 at room temperature and pressure] (2) (1) (1) (3) A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D Volume = A E R A S I H T N I E T I R W T O N O D Observation and justification(Total for Question 19 = 25 marks) TOTAL FOR SECTION B = 38 MARKS *P53493A01520* 15 Turn over<br />

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