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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 | Coated p... 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
When evaluating coated paper and poly(styrene) for disposable cups, several factors must be considered:
Raw Materials
- Coated Paper: Made from wood, a renewable resource, but requires energy for forestry and could lead to deforestation.
- Poly(styrene): Derived from crude oil, a finite resource, raising concerns about sustainability and environmental impact.
Manufacturing
- Energy Usage: Producing coated paper requires more energy (550 kJ) compared to poly(styrene) (200 kJ), making paper more resource-intensive.
- Environmental Impact: Paper production may release greenhouse gases but has the potential for energy recovery during incineration.
Disposal
- Biodegradability: Coated paper is biodegradable, reducing its impact in landfills, while poly(styrene) is non-biodegradable and can contribute to long-term pollution.
- Recyclability: Coated paper is not recyclable, whereas poly(styrene) is recyclable, which can reduce overall waste.
In conclusion, while coated paper is environmentally friendly due to its biodegradability, it requires more energy to produce and is not recyclable. Poly(styrene), on the other hand, is more energy-efficient in production and recyclable but poses long-term environmental consequences due to its non-biodegradability.
Step 2
Calculate the energy needed to produce 1.00 kg of coated paper cups.
Answer
To calculate the energy needed to produce 1.00 kg of coated paper cups, we first determine how many cups are in 1.00 kg:
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Mass of one cup = 8.3 g
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Number of cups in 1.00 kg =
rac{1000 ext{ g}}{8.3 ext{ g/cup}} \\ ext{Number of cups} = 120.48 \approx 120 \text{ cups}
Next, we calculate the total energy required for these cups:
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Energy to produce one cup = 550 kJ
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Total energy =
In standard form, this is:
- Energy =
Step 3
Explain why melamine does not melt when it is heated.
Answer
Melamine is classified as a thermosetting polymer. Thermosetting polymers have a three-dimensional network of cross-links that maintain their structure upon heating. When melamine is heated, it does not melt because the strong intermolecular forces from these cross-links prevent the polymer chains from moving freely. Instead, melamine may decompose at high temperatures rather than melting, which is characteristic of thermosetting materials.