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This question is about emissions of oxides of nitrogen from petrol and diesel engines - AQA - A-Level Chemistry - Question 1 - 2020 - Paper 3
Question 1
This question is about emissions of oxides of nitrogen from petrol and diesel engines. 1. Explain how oxides of nitrogen are formed in engines. 2. State why it is d... show full transcript
Worked Solution & Example Answer:This question is about emissions of oxides of nitrogen from petrol and diesel engines - AQA - A-Level Chemistry - Question 1 - 2020 - Paper 3
Step 1
Explain how oxides of nitrogen are formed in engines.
Answer
Oxides of nitrogen are primarily formed in engines due to the reaction of nitrogen from the air and oxygen at high temperatures. The combustion processes, especially in petrol and diesel engines, create sufficient heat to allow nitrogen and oxygen to react, forming nitrogen oxides (NO and NO₂).
Step 2
State why it is desirable to decrease emissions of oxides of nitrogen from vehicles.
Answer
It is desirable to decrease emissions of oxides of nitrogen from vehicles because these compounds contribute to air pollution, leading to the formation of acid rain and respiratory problems in humans. Reducing these emissions helps improve air quality and public health.
Step 3
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Step 5
State the meaning of the term heterogeneous catalyst.
Answer
A heterogeneous catalyst is a substance that facilitates a reaction without being consumed in the process, and exists in a different phase from the reactants. In the case of the catalytic converter, the solid platinum catalyst aids in the conversion of gaseous reactants.
Step 6
Explain why carbon particulates are formed.
Answer
Carbon particulates are formed in both diesel and petrol vehicles due to incomplete combustion of fuel. When there is insufficient oxygen present during the combustion process, carbon may not fully react to form carbon dioxide, resulting in the production of soot or particulate matter.