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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 ... 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
1. Explain how oxides of nitrogen are formed in engines.
Answer
Oxides of nitrogen are primarily formed in engines through the reaction of nitrogen from the air and oxygen at high temperatures. This typically occurs during the combustion process in internal combustion engines, where high temperatures allow nitrogen to react with oxygen, leading to the formation of various nitrogen oxides (NOx).
Step 2
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 to reduce the formation of acid rain and to mitigate respiratory problems in humans and animals. High levels of nitrogen oxides can lead to air quality issues and various health concerns.
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Step 5
4. State the meaning of the term heterogeneous catalyst.
Answer
A heterogeneous catalyst is a catalyst that exists in a different phase (solid, liquid, or gas) from the reactants involved in the reaction. Typically, heterogeneous catalysts are solid catalysts that provide a surface for the reaction to occur while the reactants are in a gas or liquid phase.
Step 6
5. Explain why carbon particulates are formed.
Answer
Carbon particulates are formed as a result of incomplete combustion of fossil fuels in both diesel and petrol engines. When the fuel is not burned completely due to insufficient oxygen supply, tiny soot particles (carbon particulates) are produced and released into the atmosphere.