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A sample of the hydrocarbon C₆H₁₂ is completely burned in dry oxygen and the product gases are collected as shown - CIE - A-Level Chemistry - Question 3 - 2018 - Paper 1
Question 3
A sample of the hydrocarbon C₆H₁₂ is completely burned in dry oxygen and the product gases are collected as shown. product gases, H₂O + CO₂ + excess of O₂ P the... show full transcript
Worked Solution & Example Answer:A sample of the hydrocarbon C₆H₁₂ is completely burned in dry oxygen and the product gases are collected as shown - CIE - A-Level Chemistry - Question 3 - 2018 - Paper 1
Step 1
What is the ratio Mₚ/Mₒ?
Answer
To find the ratio Mₚ/Mₒ, we can analyze the complete combustion of the hydrocarbon C₆H₁₂:
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Balanced Equation: The combustion of C₆H₁₂ can be expressed as:
From this equation, we see that 1 mole of C₆H₁₂ yields 6 moles of CO₂ and 6 moles of H₂O.
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Understanding the Mass Increase:
- Vessel P absorbs the water (H₂O), contributing to the mass increase of Mₚ.
- Vessel Q absorbs the carbon dioxide (CO₂), contributing to the mass increase of Mₒ.
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Mole Relationships: The increase in mass for each vessel can be related to the moles produced:
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Mₚ corresponds to the mass increase due to water produced:
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Mₒ corresponds to the mass increase due to carbon dioxide produced:
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Calculating the Ratio:
The ratio Mₚ/Mₒ becomes:
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Conclusion: Therefore, the required ratio Mₚ/Mₒ is approximately 0.41.