24.2.7—Redox equations using the relevant
- Syllabus
- 9701–2028–2029
- Objective
- 24.2.7
- Level
- A2
Construct a redox equation by combining balanced half-equations
Write one oxidation and one reduction half-equation, multiply them so electrons cancel, then add and simplify species. Atoms and charge must balance in the final equation.
Use E° values or the stated reaction to choose direction. Do not multiply electrode potentials, only the half-equation coefficients.
Zn → Zn²⁺ + 2e⁻ and Cu²⁺ + 2e⁻ → Cu combine to Zn + Cu²⁺ → Zn²⁺ + Cu.
Do not add electrons to the final equation or cancel species that occur on only one side.
ConceptA-Level CAIE Chemistry A2