1. Higher Only 

Lead is most commonly extracted from an ore called galena, PbS.

Extracting lead from the galena ore involves two steps.

Step 1: The galena ore is roasted in air to produce lead oxide, PbO.

Step 2: The lead oxide is heated in a blast furnace with carbon.

i) The reaction in step 1 is an exothermic reaction.

Draw a labelled reaction profile diagram for an exothermic reaction.

Label the activation energy and the energy change on your diagram.

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ii) In step 2 the lead oxide is reduced by carbon.

PbO + C → Pb + CO

Explain, in terms of electron transfer, why carbon is called a reducing agent in this reaction.

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