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A7 Plastics: Environmental Impact

1. Plastic materials make up a large portion of the rubbish that washes up on beaches all over the world. Explain why plastics are so resistant to degradation in the natural environment.
2. Dioxins and PCBs (polychlorinated biphenyls) are toxic chemicals that can be released when some plastics are disposed of. i. Draw diagrams of a molecule of a typical dioxin and a typical PCB. ii. Which types of plastics might release dioxins into the environment? iii. In what ways have dioxins been shown to be hazardous to health? iv. What can be done to minimise the release of dioxins into the environment? 3. i. Write balanced equations for the complete combustion of PVC (polychloroethene)
(C2H3Cl)n\textsf {(C}_\textsf2\textsf{H}_\textsf3\textsf{Cl)}_n
ii. In addition to the molecules released in the complete combustion of PVC what other harmful products might be released into the atmosphere if the air supply during combustion is limited?