Copper forms two oxides, CuO and CuO - AQA - GCSE Chemistry - Question 8 - 2019 - Paper 1
Question 8
Copper forms two oxides, CuO and CuO.
A teacher investigated an oxide of copper.
Figure 10 shows the apparatus.
This is the method used.
1. Weigh empty tube A.
2. ... show full transcript
Worked Solution & Example Answer:Copper forms two oxides, CuO and CuO - AQA - GCSE Chemistry - Question 8 - 2019 - Paper 1
Step 1
Suggest one reason why step 8 is needed.
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Answer
Step 8 is needed to ensure that all of the oxide of copper has reacted. This ensures accurate measurements of the products and that the mass has reached a stable point.
Step 2
Explain why the excess hydrogen must be burned off.
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Answer
The excess hydrogen must be burned off to prevent it from escaping into the air, as hydrogen is flammable and can create a dangerous situation. This also ensures that the results of the experiment reflect only the reaction products.
Step 3
Determine the mass of copper and the mass of water produced in this experiment.
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Answer
From Table 5:
Mass of copper = 8.66 g
Mass of water = 2.45 g
Step 4
Determine which is the correct equation for the teacher’s experiment.
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Answer
Using the masses obtained:
For equation 1 (Cu2O + H2 → 2 Cu + H2O):
Moles of Cu = 0.04, moles of H2O from the 2.54 g of copper using molar mass calculations shows that this equation is valid, with a ratio of 1:1.
Thus, it confirms that equation 1 is correct.
