CIE Nov 2016 v3 Paper 4 Q5

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Compound F contains the elements carbon, hydrogen and oxygen only. All carbon-carbon bonds in F are single bonds. The structure of F was analysed by mass spectrometry and infra-red and NMR spectroscopy. 10 PMT (a) The mass spectrum shows that the m / e value for the M peak is 90. The ratio of the heights of the M and M+1 peaks is 22.1 : 0.7. (i) Use the ratio of the heights of the M and M+1 peaks to calculate the number of carbon atoms in a molecule of F. (ii) Suggest the molecular formula of F. number of carbon atoms =[2] molecular formula = C H O [1] (b) The infra-red spectrum of F was obtained. Use the Data Booklet and your knowledge of infra-red spectroscopy to identify the type of bond and the functional group responsible for these three absorptions. absorption / cm1 appearance of the peak type of bond functional group 3350 2680 1725 broad and strong very broad and strong strong [2]UCLES 2016 9701/43/O/N/16<br /> (c) F was dissolved in deuterated trichloromethane, CDCl 3, and the proton NMR spectrum of this solution obtained. 11 PMT 14 13 12 11 10/ ppm (i) Use the Data Booklet and your answer to (a)(ii) to complete Table 1 for the proton NMR spectrum of F. The actual chemical shifts for the four absorptions in F have been added for you. Table 1/ ppm type of proton relative peak area 1.4 3.9 4.7 12.9 (ii) Describe and explain the splitting pattern for the absorption at= 1.4.[1] (iii) F was dissolved in D2O and the proton NMR spectrum of this new solution obtained. Two of the absorptions in Table 1 were not present in this spectrum. [4] Which absorptions were not present?and(iv) Suggest the structure of F. [1] [1]UCLES 2016 9701/43/O/N/16 [Turn over<br /> 12 (d) Molecules of cycloheptadiene, C7H10, consist of a seven-membered ring with carbon-carbon double bonds. two (i) Complete the skeletal formulae of two isomers of cycloheptadiene. PMT [1] The isomers P and Q were analysed using carbon-13 NMR spectroscopy. (ii) Predict the number of peaks that will be seen in the carbon-13 NMR spectra of P and Q. isomer number of peaks P Q [2] [Total: 15]UCLES 2016 9701/43/O/N/16<br /> 13 PMT Question 6 starts on the next page.UCLES 2016 9701/43/O/N/16 [Turn over<br />

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