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Two moles of compound P were placed in a sealed container - CIE - A-Level Chemistry - Question 3 - 2017 - Paper 1
Question 3
Two moles of compound P were placed in a sealed container. The container was heated and P was partially decomposed to produce Q and R only. A dynamic equilibrium bet... show full transcript
Worked Solution & Example Answer:Two moles of compound P were placed in a sealed container - CIE - A-Level Chemistry - Question 3 - 2017 - Paper 1
Step 1
What is the equation for this reversible reaction?
Answer
To determine the correct equation for the reversible reaction between compounds P, Q, and R, we need to analyze the given information about the moles present.
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Analyze the Information: We started with 2 moles of P. At equilibrium, we have x moles of R. According to the problem, the total number of moles present at equilibrium is ( \frac{2 + x}{2} ).
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Identify the Reaction: Since we are looking for a reaction where P decomposes into Q and R, we can infer that for every mole of R produced, Q might also be produced in a certain ratio, depending on the stoichiometry.
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Evaluate Options:
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Option A: P ⇌ 2Q + R
- This suggests that one mole of P produces two moles of Q and one mole of R.
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Option B: 2P ⇌ 2Q + R
- This indicates that two moles of P produce two moles of Q and one mole of R, which might not fit the stoichiometric requirement provided by the equilibrium condition.
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Option C: 2P ⇌ Q + R
- This means two moles of P produce one mole of Q and one mole of R, which could satisfy the total moles condition.
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Option D: 2P ⇌ Q + 2R
- Two moles of P yield one mole of Q and two moles of R, which could also satisfy the overall moles condition.
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Final Analysis: After examining the options, it is clear that the only equation that aligns with the description of the total moles (given as ( \frac{2 + x}{2} )) and produces the correct balance of reactions is:
- Correct Answer: Option D - 2P ⇌ Q + 2R.