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Copper oxide can be reduced to copper by reaction with hydrogen - OCR Gateway - GCSE Chemistry - Question 22 - 2018 - Paper 1
Question 22
Copper oxide can be reduced to copper by reaction with hydrogen. CuO + H₂ → Cu + H₂O A reaction mixture contains 1.59g of copper oxide and 0.20g of hydrogen. 1.27... show full transcript
Worked Solution & Example Answer:Copper oxide can be reduced to copper by reaction with hydrogen - OCR Gateway - GCSE Chemistry - Question 22 - 2018 - Paper 1
Step 1
Number of moles of CuO =
Answer
To calculate the number of moles of copper(II) oxide (CuO), we use the formula:
ext{Number of moles} = rac{ ext{mass (g)}}{ ext{molar mass (g/mol)}}The molar mass of CuO is:
Thus,
ext{Number of moles of CuO} = rac{1.59 ext{ g}}{79.5 ext{ g/mol}} \ ext{Number of moles of CuO} ext{ } ightarrow 0.02 ext{ moles}Step 2
Step 3
Number of moles of Cu =
Answer
From the reaction:
1 mole of CuO produces 1 mole of Cu, so the moles of Cu produced will be equal to the moles of CuO consumed. Based on the reaction and given that 1.27g of Cu is formed, we calculate:
The molar mass of Cu is 63.5 g/mol, hence,
ext{Number of moles of Cu} = rac{1.27 ext{ g}}{63.5 ext{ g/mol}} \ ext{Number of moles of Cu} ext{ } ightarrow 0.02 ext{ moles}Step 4
Number of moles of H₂O =
Answer
The reaction indicates that 1 mole of H₂O is produced for every mole of H₂ used. With 0.36g of H₂O produced, the molar mass of H₂O is:
Thus,
ext{Number of moles of H₂O} = rac{0.36 ext{ g}}{18 ext{ g/mol}} \ ext{Number of moles of H₂O} ext{ } ightarrow 0.02 ext{ moles}Step 5
The limiting reactant is .................... because.........................
Answer
To determine the limiting reactant, we compare the moles calculated above:
- Moles of CuO: 0.02
- Moles of H₂: 0.10
Since the amount of CuO is less than the required amount for the reaction, CuO is the limiting reactant. This is because it will be used up first before all the hydrogen has reacted.