8 6 This question is about carbon monoxide, CO, which is a toxic and colourless gas used widely in the chemical industry. (a) Draw a dot-and-cross diagram of a molecule of carbon monoxide. Use dots (•) for the carbon electrons and crosses (×) for the oxygen electrons. (2) (b) Carbon monoxide can be made by the thermal decomposition of sodium ethanedioate. Na2C2O4 → Na2CO3 + CO Calculate the atom economy, by mass, for the production of carbon monoxide in this reaction. (2) Turn over 9 (c) Carbon monoxide can also be made by the thermal decomposition of ethanal, CH3CHO, in the gas phase. CH3CHO(g) → CH4(g) + CO(g) This reaction was carried out at two different temperatures, and all other variables were kept constant. Temperature / K Rate / mol dm−3 s−1 1/Temperature (1/T) / K−1 ln rate 700 0.0108 1.43 × 10−3 850 4.90 1.59 (i) Complete the data in the table. (1) (ii) Calculate the activation energy, Ea , for the reaction without plotting a graph. Include a sign and units in your answer. The Arrhenius equation may be written as In rate = − 1 × a E R T + constant [R = 8.31 J mol−1 K−1] (3) 10 (d) Haemoglobin (Hb) found in red blood cells reacts almost irreversibly with carbon monoxide. Initial rate experiments were carried out to investigate the effect of the concentrations of Hb and CO on the rate of this reaction. Experiment [Hb] / mol dm−3 [CO] / mol dm–3 Rate / mol dm−3 s−1 1 2.09 × 10 –6 1.40 × 10 –6 8.20 × 10–7 2 4.18 × 10 –6 1.40 × 10 –6 1.64 × 10 –6 3 3.26 × 10 –6 2.80 × 10 –6 2.56 × 10 –6 (i) Deduce the order of reaction with respect to haemoglobin. (1) .................................................................................................................................................................................................................................................................................... (ii) Determine the order with respect to carbon monoxide using your answer to (d)(i) and the data in the table. Justify your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Write the rate equation for this reaction using your answers to (d)(i) and (d)(ii). (1) Turn over 11 (iv) Calculate the rate constant, k, for the reaction, using the data from Experiment 1 and the rate equation from (d)(iii). Include units in your answer. (3) (Total for Question 6 = 15 marks) 12 *7 This question is about polymers. (a) Compare and contrast how each of these monomers forms a polymer. cyclohexene 4-hydroxycyclohexanecarboxylic acid OH O C HO Include equations, showing the formation of a single repeat unit for each polymer. (6) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 13 .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 14 (b) Give three ways in which waste polymers can be utilised to improve their sustainability. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 7 = 9 marks)