Blast Furnace Chemistry: Symbol Equations for Iron Extraction
Cambridge IGCSE Chemistry 0620 · Three sections, 15 questions · Core & Supplement
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Write the symbol equation for the burning of coke in the blast furnace to provide heat.
💡 Hint: Coke is carbon. It burns completely in the oxygen-rich lower zone.
Why is the combustion of coke important for the blast furnace operation? Give two reasons.
💡 Hint: Think: energy + what happens to a product of this reaction.
State the type of reaction that occurs when coke burns in the blast furnace.
💡 Hint: Consider the energy change.
Hot air is blasted into the bottom of the furnace. Explain why air is used rather than pure oxygen, even though oxygen is the active reactant.
💡 Hint: Think about cost and what makes up air besides oxygen.
What is the name of the substance added to the blast furnace that reacts with acidic impurities in the iron ore?
💡 Hint: It is a carbonate of a Group 2 metal.
Write the symbol equation for the formation of the main reducing agent in the blast furnace.
💡 Hint: CO₂ reacts with more carbon (coke) in the high-temperature upper zone.
Name the main reducing agent in the blast furnace.
💡 Hint: It is a gas formed from the reaction of coke and carbon dioxide.
Explain what it means for carbon monoxide to act as a reducing agent in terms of oxygen transfer.
💡 Hint: What does a reducing agent do to the substance being reduced?
In terms of oxidation states, show that carbon monoxide is oxidised during the reduction of iron(III) oxide.
💡 Hint: Assign oxidation states to C in CO and in CO₂.
Describe the hazard associated with carbon monoxide and explain why this is a concern for workers near a blast furnace.
💡 Hint: What happens when CO enters the human bloodstream?
Write the symbol equation for the reduction of iron(III) oxide by carbon monoxide in the blast furnace.
💡 Hint: Iron(III) oxide is Fe₂O₃. The products are iron and carbon dioxide.
What type of reaction is: Fe₂O₃ + 3CO → 2Fe + 3CO₂? State one term that applies to Fe₂O₃ in this reaction.
💡 Hint: Think about what happens to the iron in terms of gaining or losing oxygen.
The iron produced in the blast furnace sinks to the bottom and is tapped off. Explain, in terms of particles, why molten iron sinks below the molten slag.
💡 Hint: Compare the densities of iron and slag.
Write the full sequence of reactions that converts limestone into slag (calcium silicate). Include: (i) the thermal decomposition of limestone, (ii) the reaction of the product with silicon dioxide impurities.
💡 Hint: Limestone → quicklime → slag. Two separate equations needed.
A student claims: 'The blast furnace produces pure iron.' Evaluate this claim. In your answer, refer to: (a) the composition of the iron produced, (b) how this can be improved, and (c) one use of the improved product.
💡 Hint: What impurities remain? What process removes them?
📋 Equation Cheat Sheet (Memorise These)
Cambridge IGCSE Chemistry 0620 · Topic 9.6 · Limitless Chemistry Professor
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