9.4

Uses of metals

Cambridge IGCSE Chemistry (0620)  · Unit 9: Metals  · 10 flashcards

Uses of metals is topic 9.4 in the Cambridge IGCSE Chemistry (0620) syllabus , positioned in Unit 9 — Metals , alongside Properties of metals, Reactivity series and Extraction of metals.  In one line: A displacement reaction is when a more reactive metal displaces a less reactive metal from its aqueous salt solution. For.

This topic is examined in Paper 1 (multiple-choice) and Papers 3/4 (theory), plus Paper 5 or Paper 6 (practical / alternative to practical).

The deck below contains 10 flashcards — 1 definition, 8 key concepts and 1 identification card — covering the precise wording mark schemes reward.  Use the definition card to lock down command-word answers (define, state), then move on to the concept and application cards to handle explain, describe and compare questions.

Key definition

A displacement reaction involving aqueous ions

A displacement reaction is when a more reactive metal displaces a less reactive metal from its aqueous salt solution. For

Example: Iron will displace copper from copper sulfate solution: Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)

What the Cambridge 0620 syllabus says

Official 2026-2028 spec

These are the exact learning objectives Cambridge sets for this topic. Match the command word (Describe, Explain, State, etc.) in your answer to score full marks.

  1. State State the order of the reactivity series as: potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver, gold
  2. Describe Describe the reactions, if any, of: (a) potassium, sodium and calcium with cold water (b) magnesium with steam (c) magnesium, zinc, iron, copper, silver and gold with dilute hydrochloric acid and explain these reactions in terms of the position of the metals in the reactivity series
  3. Deduce Deduce an order of reactivity from a given set of experimental results
  4. Describe Describe the relative reactivities of metals in terms of their tendency to form positive ions, by displacement reactions, if any, with the aqueous ions of magnesium, zinc, iron, copper and silver Supplement
  5. Explain Explain the apparent unreactivity of aluminium in terms of its oxide layer Supplement
Key Concept Flip

State the order of the reactivity series (most to least reactive).

Answer Flip

Potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver, gold.

Key Concept Flip

What happens when potassium, sodium, and calcium react with cold water?

Answer Flip

Potassium, sodium, and calcium react vigorously with cold water, producing hydrogen gas and a metal hydroxide. Potassium reacts the most vigorously, followed by sodium and then calcium.

Example: 2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g)
Key Concept Flip

What happens when magnesium reacts with steam?

Answer Flip

Magnesium reacts with steam (H₂O in gaseous form) to produce magnesium oxide (MgO) and hydrogen gas (H₂).

Example: Mg(s) + H₂O(g) → MgO(s) + H₂(g)
Key Concept Flip

Which of these metals react with dilute hydrochloric acid: magnesium, zinc, iron, copper, silver, gold?

Answer Flip

Magnesium, zinc, and iron react with dilute hydrochloric acid to produce hydrogen gas and a metal chloride. Copper, silver, and gold do not react because they are below hydrogen in the reactivity series.

Example: Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)
Key Concept Flip

Explain why some metals react with dilute hydrochloric acid and others don't.

Answer Flip

Metals above hydrogen in the reactivity series can displace hydrogen ions (H⁺) from the acid to form hydrogen gas and a metal salt. Metals below hydrogen cannot displace the hydrogen ions.

Example: Iron can displace hydrogen, while copper can't.
Key Concept Flip

How can you deduce an order of reactivity from experimental results of metal reactions with acids?

Answer Flip

Observe the rate of reaction (

Example: speed of bubble formation, heat produced). A more vigorous reaction (faster bubble formation, more heat) indicates a more reactive metal. Comparing different metals reacting with the same acid can establish a relative order.
Key Concept Flip

Relate a metal's reactivity to its tendency to form positive ions.

Answer Flip

More reactive metals have a greater tendency to lose electrons and form positive ions (cations). This is why they readily react with other substances.

Example: Sodium easily forms Na⁺, making it very reactive.
Definition Flip

What is a displacement reaction involving aqueous ions?

Answer Flip

A displacement reaction is when a more reactive metal displaces a less reactive metal from its aqueous salt solution. For

Example: Iron will displace copper from copper sulfate solution: Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)
Key Concept Flip

Describe a displacement reaction between magnesium and copper(II) ions.

Answer Flip

Magnesium is more reactive than copper. When magnesium metal is added to a solution containing copper(II) ions (

Example: copper(II) sulfate), magnesium displaces the copper ions, forming magnesium ions and solid copper: Mg(s) + Cu²⁺(aq) → Mg²⁺(aq) + Cu(s)
Key Concept Flip

Explain why aluminium appears unreactive, even though it is high in the reactivity series.

Answer Flip

Aluminium readily reacts with oxygen in the air to form a thin, strong, and unreactive layer of aluminium oxide (Al₂O₃) on its surface. This oxide layer prevents further reaction with other substances, making aluminium appear unreactive.

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9.3 Extraction of metals 9.5 Corrosion

Key Questions: Uses of metals

What is a displacement reaction involving aqueous ions?

A displacement reaction is when a more reactive metal displaces a less reactive metal from its aqueous salt solution. For

Example: Iron will displace copper from copper sulfate solution: Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)

Tips to avoid common mistakes in Uses of metals

More topics in Unit 9 — Metals

Uses of metals sits alongside these Chemistry decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.

9.1 Properties of metals

10 flashcards
9.2 Reactivity series

17 flashcards
9.3 Extraction of metals

8 flashcards
9.5 Corrosion

10 flashcards

Cambridge syllabus keywords to use in your answers

These are the official Cambridge 0620 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.

uses copper wiring plumbing aluminium aircraft iron steel construction stainless steel alloy

Key terms covered in this Uses of metals deck

Every term below is defined in the flashcards above. Use the list as a quick recall test before your exam — if you can't define one of these in your own words, flip back to that card.

Displacement reaction involving aqueous ions

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