This exam focus covers Worked Model Answer within Displacement Reactions for GCSE Chemistry. Revise Displacement Reactions in Chemical Changes for GCSE Chemistry with 22 exam-style questions and 20 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 12 of 13 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
📝 Worked Model Answer
Question: "Explain why iron can displace copper from copper sulfate solution." (4 marks)
Iron is more reactive than copper [1], so it has a greater tendency to lose electrons. Iron atoms lose electrons more readily than copper ions can hold them. [1] Iron is therefore oxidised — each iron atom loses two electrons to become an Fe²⁺ ion: Fe → Fe²⁺ + 2e⁻. [1] The copper ions in solution gain those electrons and are reduced, forming solid copper metal: Cu²⁺ + 2e⁻ → Cu. [1]
Examiner note: All four mark points must be present: iron is more reactive, iron loses electrons more readily, iron is oxidised (with half equation), copper ions are reduced (with half equation). The word "displaced" alone is not sufficient without explaining the electron transfer. The sulfate ion is a spectator ion and does not need to be mentioned.
Practice questions for Displacement Reactions
Which statement correctly describes a displacement reaction?
In the reaction between zinc and copper sulfate solution, explain which species is oxidised and which is reduced. Include half equations in your answer. [3 marks]