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Shopping bags can be made from different types of plastics - OCR Gateway - GCSE Chemistry: Combined Science - Question 15 - 2020 - Paper 1
Question 15
Shopping bags can be made from different types of plastics. The table shows information about three different plastic bags. Plastic bag Weight (g) Volume (cm³) F... show full transcript
Worked Solution & Example Answer:Shopping bags can be made from different types of plastics - OCR Gateway - GCSE Chemistry: Combined Science - Question 15 - 2020 - Paper 1
Step 1
Calculate the energy used (in kJ) for every 100 bags of Plastic bag C made.
Answer
To calculate the energy used for every 100 bags of Plastic bag C made, we first convert the energy from Joules to kilojoules.
Given that Plastic bag C uses 31600 J for each bag made, for 100 bags, the energy would be:
a 100 = 31600 imes 100 = 3160000 ext{ J}
Next, converting Joules to kilojoules (1 kJ = 1000 J):
a 100 = rac{3160000 ext{ J}}{1000} = 3160 ext{ kJ}
Finally, writing the answer in standard form:
a 100 = 3.16 imes 10^3 ext{ kJ}
Step 2
Explain why both students could be correct.
Answer
Both students could be correct based on different considerations when evaluating the plastic bags.
Plastic Bag A:
- It is lightweight (8 g), which could make it easier to carry and may require less energy for production, thus making it more energy-efficient.
- It has a large volume (19000 cm³) which allows for multiple items to be carried at once, making it convenient.
Plastic Bag B:
- Although it is heavier (35 g), it uses less energy per bag made compared to Plastic Bag C, with an energy usage of 17000 J per 100 bags.
- It may be more durable or suitable for heavier items compared to Bag A, which could make it more practical for certain purposes.
In conclusion, student A values lightweight and ease of use, while student B values durability and energy efficiency, allowing both opinions to be valid.