Complete the ionic equation for the reaction between zinc and copper sulfate solution.
Include state symbols.
Zn(s) + Cu²⁺(aq) → ______ + ______
How to approach this question
1. This is a displacement reaction. Zinc is more reactive than copper.
2. The zinc atom (Zn) will lose electrons to become a zinc ion. What is the charge on a zinc ion?
3. The copper ion (Cu²⁺) will gain electrons to become a copper atom.
4. Write the symbols for the products.
5. Determine the state symbols. The zinc ion will be dissolved in water (aqueous), and the copper atom will be a solid metal.
Full Answer
Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s)
The full equation is Zn(s) + CuSO₄(aq) → ZnSO₄(aq) + Cu(s).
To write the ionic equation, we only include the species that change. The sulfate ion (SO₄²⁻) is a spectator ion because it is (aq) on both sides and does not change.
- Solid zinc, Zn(s), is a reactant.
- Aqueous copper(II) ions, Cu²⁺(aq), are reactants.
- Zinc is more reactive than copper, so it displaces the copper. The zinc atom loses two electrons to form a zinc ion, Zn²⁺. Since it is in solution, its state symbol is (aq).
- The copper(II) ion gains two electrons to form a solid copper atom, Cu(s).
So the complete ionic equation is: Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s).
Common mistakes
✗ Forgetting the charges on the ions (Zn²⁺).
✗ Getting the state symbols wrong, especially for the products.
✗ Including the spectator ion (SO₄²⁻).
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