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This question is about atmospheric pollution - AQA - GCSE Chemistry - Question 6 - 2020 - Paper 2
Question 6
This question is about atmospheric pollution. Figure 3 shows a limestone carving which has been damaged by atmospheric pollution. The carving has been: - blackene... show full transcript
Worked Solution & Example Answer:This question is about atmospheric pollution - AQA - GCSE Chemistry - Question 6 - 2020 - Paper 2
Step 1
Explain why soot is formed when some fossil fuels are burned.
Answer
Soot is formed during the combustion of fossil fuels primarily due to incomplete combustion. When fossil fuels do not burn completely, there is insufficient oxygen available for the reaction. This leads to the production of elemental carbon, which accumulates as soot.
Step 2
Explain how reducing the amount of sulfur in fossil fuels reduces the erosion of limestone.
Answer
Sulfur in fossil fuels reacts with oxygen during combustion to form sulfur dioxide (SO₂). When SO₂ is emitted into the atmosphere, it can lead to acid rain as it interacts with water vapor. This acid rain, which is acidic in nature, can react with limestone, causing erosion. By reducing the sulfur content in fossil fuels, less sulfur dioxide is produced, leading to less acid rain and consequently less erosion of limestone.
Step 3
Explain why oxides of nitrogen are formed in car engines.
Answer
Oxides of nitrogen are formed in car engines due to the high temperatures at which engines operate. At these elevated temperatures, nitrogen from the air reacts with oxygen, creating nitrogen oxides (NOx). This reaction typically occurs in the combustion chamber of the engine under high pressure and temperature conditions.