Chemistry 5070 · O Level · Extraction of metals

Extraction of metals — practice question

Iron is obtained in a blast furnace by reducing iron(III) oxide with carbon monoxide. $\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$
(a(i))[1]

This is a redox reaction. State what is meant by the term redox reaction.

(a(ii))[1]

Explain how carbon monoxide acts as a reducing agent in this reaction.

(b)[3]

Calcium carbonate is added to the blast furnace. Calcium carbonate then undergoes thermal decomposition. $\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2$ The thermal decomposition of calcium carbonate is endothermic. Complete the reaction pathway diagram in Fig. 2.1 so that it shows: • the reactant and the products • a labelled arrow for the activation energy, $E_a$ • a labelled arrow for the enthalpy change, $\Delta H$.

(c)[2]

Describe how slag is made in the blast furnace. Include a symbol equation in your response.

(d)[2]

Iron is a transition element. Transition elements form coloured compounds. State two other physical properties that are typical of transition elements and not of Group I metals.

(e(i))[2]

The equation represents the decomposition of iron pentacarbonyl, $\text{Fe(CO)}_5$, in a sealed container. $\text{Fe(CO)}_5(l) \rightleftharpoons \text{Fe}(s) + 5\text{CO}(g)$ Predict and explain how the equilibrium position changes when the pressure is lowered. The temperature stays unchanged.

(e(ii))[2]

This reaction can be used to make pure iron. Describe and explain, with reference to the equation, how a sample of pure iron that contains no $\text{Fe(CO)}_5(l)$ is obtained from the equilibrium mixture.

(f)[2]

Iron reacts with hot concentrated sulfuric acid. The products are iron(III) sulfate, sulfur dioxide and a liquid that turns anhydrous copper(II) sulfate blue. Construct the symbol equation for this reaction.

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: oxidation and reduction happen at the same time

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI