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Gases and ammonia (a) Hydrogen reacts with oxygen to form water vapour - Edexcel - GCSE Chemistry - Question 6 - 2014 - Paper 1
Question 6
Gases and ammonia (a) Hydrogen reacts with oxygen to form water vapour. 2H₂(g) + O₂(g) → 2H₂O(g) If 200 cm³ of hydrogen react completely with 100 cm³ of oxygen, w... show full transcript
Worked Solution & Example Answer:Gases and ammonia (a) Hydrogen reacts with oxygen to form water vapour - Edexcel - GCSE Chemistry - Question 6 - 2014 - Paper 1
Step 1
Maximum Volume of Water Vapour
Answer
To determine the maximum volume of water vapour formed, we can use the stoichiometry of the reaction. The balanced equation shows that 2 volumes of hydrogen react with 1 volume of oxygen to produce 2 volumes of water vapour.
Since 200 cm³ of hydrogen reacts, we need to calculate the corresponding volume of water vapour produced:
- From the stoichiometry, we see that 2 cm³ of H₂ produces 2 cm³ of H₂O.
- Thus, 200 cm³ of H₂ will produce 200 cm³ of water vapour.
Therefore, the answer is B 200 cm³.
Step 2
Maximum Volume of Hydrogen from Zinc
Answer
To calculate the maximum volume of hydrogen produced, we follow these steps:
-
Determine the number of moles of zinc from its mass:
Moles of Zn = ( \frac{mass}{molar\ mass} = \frac{13.0 g}{65.0 g/mol} = 0.200 \text{ mol} )
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From the balanced equation, we see that 1 mole of Zn produces 1 mole of H₂.
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Therefore, the number of moles of hydrogen produced is also 0.200 mol.
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The volume of hydrogen at room temperature and pressure (RTP) can be calculated knowing that 1 mole occupies 24 dm³:
Volume of H₂ = ( 0.200\ ext{ mol} \times 24\ ext{ dm}^3/\text{mol} = 4.8\ ext{ dm}^3 )
Thus, the maximum volume of hydrogen formed is 4.8 dm³.