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Discuss the role of iron as a heterogeneous catalyst in the Haber process - AQA - A-Level Chemistry - Question 4 - 2021 - Paper 1
Question 4
Discuss the role of iron as a heterogeneous catalyst in the Haber process. Your answer should include: - the meaning of the term heterogeneous catalyst - how iron ... show full transcript
Worked Solution & Example Answer:Discuss the role of iron as a heterogeneous catalyst in the Haber process - AQA - A-Level Chemistry - Question 4 - 2021 - Paper 1
Step 1
the meaning of the term heterogeneous catalyst
Answer
A heterogeneous catalyst is a catalyst that exists in a different phase from the reactants. In the Haber process, iron provides a surface for the reaction to occur, facilitating the combination of hydrogen and nitrogen gases into ammonia.
Step 2
how iron acts as a heterogeneous catalyst
Answer
Iron acts as a heterogeneous catalyst by adsorbing hydrogen and nitrogen atoms onto its surface. This process weakens the bonds in the diatomic molecules (H₂ and N₂), allowing them to react more easily. The ammonia (NH₃) produced then desorbs from the iron surface, leaving it available for further reactions.
Step 3
the factors that affect the efficiency and lifetime of the catalyst
Answer
The efficiency of the iron catalyst is influenced by temperature and pressure; higher temperatures increase reaction rates, while high pressures favor ammonia production. Additionally, impurities can poison the catalyst, reducing its activity. The lifetime of the catalyst is also affected by sintering, where particles agglomerate and reduce surface area over time.