6 2 Plant‑based products provide a sustainable alternative to oil‑based plastics. In a single year, over 7600 million single‑use plastic bags were given to customers by supermarkets in England. The mean mass of each bag was 5.5 g. (a) Calculate the total mass in kilograms of plastic bags given out to customers. Give your answer in standard form. (2) Answer .............................................................. kg (b) A sustainable alternative is a plastic material that contains more than 30% plant‑based polymers. Potato starch is a source of these polymers. (i) Describe the structure of starch. 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Turn over 7 (ii) Explain why this plastic material is only partially sustainable. 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(c) The tensile strength of plant fibres can be tested using different methods. One method is to attach both ends of a fibre to clamps horizontally and hang increasing numbers of masses until the fibre breaks. A second method is to attach one end of a fibre to a clamp and the other to a forcemeter, pulling on the forcemeter until the fibre breaks. Explain which method will give more accurate results. 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(Total for Question 2 = 9 marks)