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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
Step 2
How iron acts as a heterogeneous catalyst
Answer
Iron promotes the synthesis of ammonia from nitrogen and hydrogen by providing a surface for the reaction to occur. The adsorption of the reactant gases onto the iron catalyst allows for bond breaking and formation to proceed at a faster rate, thereby lowering the activation energy necessary for the reaction.
Step 3
The factors that affect the efficiency and lifetime of the catalyst
Answer
Several factors influence the efficiency and lifetime of iron as a catalyst in the Haber process:
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Temperature and Pressure: Increasing temperature generally increases reaction rates but can also lead to catalyst deactivation due to sintering. Higher pressure favors the formation of ammonia, enhancing the effectiveness of the catalyst.
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Surface Area: The effectiveness of iron as a catalyst is linked to its surface area. A larger surface area facilitates more adsorption sites for reactants.
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Catalyst Poisoning: The presence of impurities can lead to catalyst poisoning, which reduces catalytic activity. For instance, sulfur compounds can adsorb to the surface of the iron, preventing the reaction from proceeding efficiently.
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Deactivation Over Time: The iron catalyst may become less effective over time due to structural changes or accumulation of byproducts.