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Limestone is a sedimentary rock - Edexcel - GCSE Chemistry - Question 5 - 2018 - Paper 1
Question 5
Limestone is a sedimentary rock. Limestone is a form of calcium carbonate. (i) A sample of limestone has a layered structure and contains fossils. Explain how this ... show full transcript
Worked Solution & Example Answer:Limestone is a sedimentary rock - Edexcel - GCSE Chemistry - Question 5 - 2018 - Paper 1
Step 1
Explain how this limestone has formed.
Answer
Limestone forms through the build-up of sediment over long periods of time. Layers of sediment accumulate, and high pressure from the layers above compacts them. Additionally, fossils found in limestone are created from the remains of marine organisms, like skeletons or shells, deposited within the sediment.
Step 2
Step 3
Explain why the mass of calcium oxide at the end of the reaction is less than the original mass of calcium carbonate.
Answer
During the decomposition of calcium carbonate, a gas, specifically carbon dioxide (CO₂), is formed and escapes into the atmosphere. This loss of gas results in a lower mass of the solid calcium oxide compared to the original mass of calcium carbonate.