OCR A Jun 2016 Paper 2 Q6

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18 This question is about several unsaturated hydrocarbons. (a) The mass spectrum of an alkene is shown below. 100 relative intensity 80 60 40 20 II 10 20 30 40 50 m / z 60 70 80 (i) The empirical formula of the alkene is CH2. Use the empirical formula and the mass spectrum to confirm the molecular formula as C6H12.[1]OCR 2016<br />
 (ii) Further analysis showed that the alkene was hex-2-ene. 19 Suggest possible structures for the species responsible for the labelled peaks I and II in the mass spectrum of hex-2-ene shown opposite. peak I peak II (b) Hex-2-ene shows E/Z isomerism. (i) Draw the skeletal formulae of E-hex-2-ene and Z-hex-2-ene. [3] [2] E-hex-2-ene Z-hex-2-ene (ii) State and explain the features of a hex-2-ene molecule that lead to E and Z isomers.[2] Turn overOCR 2016<br />
 (c) A section of a polymer that can be made from an unsaturated hydrocarbon B is shown below. 20 (i) Add brackets to the section of the polymer to show one repeat unit. [1] (ii) Draw the structure of hydrocarbon B. (iii) The polymer has a relative molecular mass of 50,000. Calculate the number of monomer molecules required to make one molecule of the polymer. [1] number of monomer molecules =[1] [Total: 11]OCR 2016<br />

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