10 Calcium carbonate decomposes on heating to form calcium oxide and carbon dioxide - Edexcel - GCSE Chemistry - Question 10 - 2019 - Paper 1
Question 10
10 Calcium carbonate decomposes on heating to form calcium oxide and carbon dioxide.
CaCO₃(s) → CaO(s) + CO₂(g)
(a) 8.000g of CaCO₃ was heated strongly for about 1... show full transcript
Worked Solution & Example Answer:10 Calcium carbonate decomposes on heating to form calcium oxide and carbon dioxide - Edexcel - GCSE Chemistry - Question 10 - 2019 - Paper 1
Step 1
Calculate the mass of carbon dioxide gas given off.
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Answer
To find the mass of carbon dioxide produced, we subtract the mass of the solid remaining from the initial mass of calcium carbonate:
A possible reason for the mass of solid left in the crucible.
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Answer
The mass of solid left in the crucible is less than the theoretical mass expected due to the possibility that:
A. some solid was lost from the crucible.
Step 4
Explain the trend shown by the data in Figure 11.
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Answer
The trend in Figure 11 indicates that the mass of solid remaining decreases over time. This suggests that the decomposition of calcium carbonate is occurring as it is heated, resulting in the release of gases such as CO₂. Initially, the solid mass is high, but as time progresses, the mass steadily decreases, reflecting the reaction's progress.
Step 5
State why it is impossible to be sure from this data that the reaction is complete.
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It is impossible to be sure that the reaction is complete because, although the mass decreases over time, the data does not show a point where the mass stabilizes or stops decreasing. Therefore, there might still be calcium carbonate that has not yet reacted.
Step 6
Calculate the relative formula mass of calcium carbonate, CaCO₃.
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The relative formula mass of calcium carbonate is calculated by summing the atomic masses of its constituent elements:
