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Disposable cups are made from coated paper or poly(styrene) - AQA - GCSE Chemistry - Question 10 - 2018 - Paper 2
Question 10
Disposable cups are made from coated paper or poly(styrene). Table 6 shows information on the life cycle assessments (LCAs) of disposable cups. Table 6 | ... show full transcript
Worked Solution & Example Answer:Disposable cups are made from coated paper or poly(styrene) - AQA - GCSE Chemistry - Question 10 - 2018 - Paper 2
Step 1
Evaluate the use of coated paper compared with poly(styrene) to make disposable cups.
Answer
The evaluation of coated paper and poly(styrene) cups can be analyzed through several factors:
Raw Materials
- Coated Paper Cups: Made from wood, a renewable resource. However, its use for cup production can lead to deforestation and biodiversity loss if not sustainably sourced.
- Poly(styrene) Cups: Derived from crude oil, a finite resource that may become scarce, thus unsustainable over time.
Manufacturing
- The production of poly(styrene) is energy-intensive and contributes more to pollution, whereas the energy required for paper production, while still significant, may involve renewable sources. This is crucial from an LCA perspective since it reflects on long-term environmental impact.
Disposal
- Coated paper cups are biodegradable, allowing them to decompose and return to the ecosystem, thus minimizing landfill impact. In contrast, poly(styrene) does not decompose, lingering in landfills and potentially causing long-term pollution. This difference is pivotal in the lifecycle analysis of these products.
Conclusion
Overall, while both options have disadvantages, coated paper cups may be preferable due to their biodegradability and renewable raw material, although ensuring sustainable forestry practices is essential.
Step 2
Calculate the energy needed to produce 1.00 kg of coated paper cups.
Answer
To calculate the energy required to produce 1.00 kg of coated paper cups:
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Determine the number of cups in 1 kg:
ext{Mass of 1 coated paper cup} = 8.3 ext{ g}
ext{Number of cups in 1 kg} = rac{1000 ext{ g}}{8.3 ext{ g}} ext{ cups}
ext{Number of cups} ext{ (rounded)} ext{s approx = } 120.48 ext{ cups}
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Calculate the energy for one cup:
- The energy to produce one coated paper cup is 550 kJ.
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Total energy:
ext{Total energy} = 120.48 ext{ cups} imes 550 ext{ kJ/cup} ext{ } = 66304 ext{ kJ}
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Convert to standard form:
66304 ext{ kJ} = 6.6304 imes 10^4 ext{ kJ}.
Thus, the energy needed to produce 1.00 kg of coated paper cups is approximately .
Step 3
Explain why melamine does not melt when it is heated.
Answer
Melamine is a thermosetting polymer, which means that it contains crosslinks or bonds between polymer chains that prevent it from melting upon heating. When heated, instead of melting, melamine undergoes a chemical change that can cause it to decompose rather than transition into a liquid state. This property is due to the strong covalent bonds in its structure, which maintain its integrity despite temperature increases, making it suitable for applications where heat resistance is vital.