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Stage 1 takes in heat energy, it is endothermic - Edexcel - GCSE Chemistry - Question 7 - 2020 - Paper 1
Question 7
Stage 1 takes in heat energy, it is endothermic. Explain the effect of increasing the temperature on the yield of the products of stage 1. (i) The overall equation... show full transcript
Worked Solution & Example Answer:Stage 1 takes in heat energy, it is endothermic - Edexcel - GCSE Chemistry - Question 7 - 2020 - Paper 1
Step 1
Explain the effect of increasing the temperature on the yield of the products of stage 1.
Answer
Increasing the temperature of an endothermic reaction shifts the equilibrium position to the right, favoring the production of the products. This is because the reaction absorbs heat; thus, supplying more heat drives the reaction forward, resulting in an increased yield of both hydrogen and carbon monoxide.
Step 2
Calculate the maximum volume of hydrogen in dm³, measured at room temperature and pressure, that could be made in this reaction.
Answer
First, we need to calculate the number of moles of methane in 0.40 g:
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Molar mass of CH₄ = 12.01 (C) + 4.00 (H) = 16.05 g/mol.
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Number of moles of CH₄ = 0.40 g / 16.05 g/mol = 0.0249 mol.
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According to the balanced equation, 1 mole of CH₄ produces 4 moles of H₂.
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Therefore, 0.0249 mol of CH₄ will produce:
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At room temperature and pressure, 1 mole of gas occupies approximately 24 dm³.
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Thus, the volume of hydrogen produced will be:
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Rounding gives us a maximum volume of approximately 2.4 dm³.
Step 3
Evaluate the advantages and disadvantages of providing electrical energy in a spacecraft using hydrogen-oxygen fuel cells rather than chemical cells.
Answer
Advantages
- Maintenance-free setup: Once set up, fuel cells require no regular maintenance compared to chemical cells, which need periodic replacements.
- Longevity: Fuel cells can last longer, as they do not degrade like chemical cells.
- Efficiency: Fuel cells produce energy as long as hydrogen and oxygen are supplied.
- Space-saving and valuable: Used chemical cells can take up valuable space on a spacecraft and cannot be reused once depleted.
Disadvantages
- Supply requirements: Hydrogen and oxygen must be supplied and transported into the spacecraft, which adds logistical complexity.
- Handling and storage: Both gases are flammable and require careful handling and storage.
- Manufacturing complexity: Fuel cells can be more complex and expensive to manufacture compared to conventional chemical cells.
Conclusion
Given these factors, the choice between using fuel cells and chemical cells in spacecraft depends on mission requirements and available resources.