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2. (a) Granite is an igneous rock - Edexcel - GCSE Chemistry - Question 2 - 2016 - Paper 1
Question 2
2. (a) Granite is an igneous rock. The size of crystals in granite vary. Describe how a sample of granite which contains large crystals was formed. (b) Limestone an... show full transcript
Worked Solution & Example Answer:2. (a) Granite is an igneous rock - Edexcel - GCSE Chemistry - Question 2 - 2016 - Paper 1
Step 1
Describe how a sample of granite which contains large crystals was formed.
Answer
Granite is formed from magma, which is molten rock beneath Earth's surface. As the magma cools slowly, it solidifies into a crystalline structure. The slow cooling process allows large crystals to form, as the minerals have sufficient time to grow and expand. This typically occurs intrusively within the Earth's crust, leading to the formation of granites with significant crystal sizes.
Step 2
Describe how marble is formed from limestone.
Answer
Marble is formed from limestone through a process known as metamorphism. When limestone is subjected to high heat and pressure, typically associated with tectonic movements, it undergoes a physical and chemical transformation. This process compacts the limestone and facilitates the recrystallization of minerals, resulting in the formation of marble, which is characterized by its interlocking crystals.
Step 3
Explain why calcium carbonate can be used in this way.
Answer
Calcium carbonate can be used to treat waste gases such as sulfur dioxide because it reacts with this acidic gas to form calcium sulfate and water in a neutralization reaction. This reaction helps to remove harmful gases from emissions, reducing environmental pollution.